Showing papers in "Journal of Neural Transmission in 2001"
TL;DR: There was a significant association between FOG and the presence of dyskinesia, early morning foot dystonia, and significant postural instability, and longer duration of treatment with dopamine agonists contribute to the appearance of FOG.
Abstract: Background. Freezing of Gait (FOG) is one of the most disturbing and least understood symptom in advanced stage of Parkinson's disease (PD). The contribution of the underlying pathological process and the antiparkinsonian treatment to the development of FOG are controversial.
349 citations
TL;DR: The knowledge about the neurotoxic mechanisms of MPTP such as mitochondrial dysfunction with breakdown of energy metabolism and free radical production will help to understand the underlying mechanisms of PD, which are not fully understood yet.
Abstract: Animal models are a very important approach to study the pathogenesis and therapeutic intervention strategies of human diseases. Since many human disorders do not arise spontaneously in animals, characteristic functional changes have to be mimicked by neurotoxic agents. For instance, the application of the dopaminergic neurotoxin MPTP (1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine) is able to produce striking similarities to Parkinson's disease (PD) diagnosed in humans. MPTP is thought to selectively damage dopaminergic neurons predominantly those originating in the substantia nigra pars compacta (SNc) which leads to impaired dopaminergic neurotransmission accompanied by a loss of dopaminergic nerve terminals in the striatum. MPTP-induced neurochemical, behavioral, and histopathological alterations replicate very closely the clinical symptoms of PD patients, which will be discussed in this paper and render the MPTP model currently the most favored PD model to study therapeutic intervention strategies in an easy and reliable way in preclinical studies. We and many other research groups propose that the knowledge about the neurotoxic mechanisms of MPTP such as mitochondrial dysfunction with breakdown of energy metabolism and free radical production will help us to understand the underlying mechanisms of PD, which are not fully understood yet. In particular, the novel aspects of inflammatory processes and the involvement of reactive nitrogen species in addition to reactive oxygen species seem to be important milestones for a better understanding of the neurodegenerative effects of MPTP. In this review we focus on the MPTP mouse model which is easy practicable and widely used in neuroscience research and draw comparisons to the human pathology in PD.
267 citations
TL;DR: The hypothesis that alcohol use affects areas involved in brain reward circuits and that their stimulus-induced activation may be associated with an increased risk for relapse is supported.
Abstract: Alcohol-associated cues may act as conditioned stimuli that activate the brain reward system and motivate alcohol intake in alcoholics. Alcohol-associated visual stimuli were presented during functional magnetic resonance imaging. An activation of the ventral putamen was observed in alcoholics but not in control subjects. Patients with a strong activation of the ventral putamen relapsed during the next three months. This observation supports the hypothesis that alcohol use affects areas involved in brain reward circuits and that their stimulus-induced activation may be associated with an increased risk for relapse.
196 citations
TL;DR: Results of in vitro studies indicate that MAPK/ERK-P, SAPK/JNK-P and p-38-P are differentially expressed in association with tau deposits in tauopathies, and CaM kinase II is present in neurons but not in glial cells, thus suggesting no role of CaM Kinase II in t Tau phosphorylation ofglial cells.
Abstract: Calcium/calmodulin-dependent kinase II (alpha- and beta-CaM kinase II), and phosphorylated mitogen-activated extracellular signal-regulated protein kinase (MAPK/ERK-P), phosphorylated protein kinase of 38 kDa (p38-P) and phosphorylated stress-activated protein kinase (SAPK/JNK-P) expression have been examined in Alzheimer disease (AD), Pick's disease (PiD), progressive supranuclear palsy (PSP) and corticobasal degeneration (CBD). The study was carried out to increase understanding of the signals that may regulate tau phosphorylation in tauopathies. MAPK/ERK-P was found in a subset of neurons and glial cells bearing abnormal tau deposition, but rarely in neurofibrillary tangles. Strong p38-P immunoreactivity was observed in about 50-70% of neurons with neurofibrillary tangles and in dystrophic neurites of senile plaques in AD. Strong p38-P immunoreactivity was seen in practically all Pick bodies in PiD, and in most neurons with neurofibrillary degeneration or with tau deposits (pre-tangle neurons) in PSP and CBD, as revealed with single and double-labeling immunohistochemistry to p38-P and tau. In addition, strong p38-P immunoreactivity was present in tau-positive astrocytes and in coiled bodies in PSP and CBD. Single and double-labeling immunohistochemistry to MAPK/ERK-P and p38-P disclosed that MAPK/ERK-P appeared at early stages of tau phosphorylation in neurons and glial cells in tauopathies, and that MAPK/ERK-P and p38-P co-localize only in a subset of neurons and glial cells with phosphorylated tau deposits. SAPK/JNK-P immunoreactivity was seen in a subset of neurons, including many neurons with neurofibrillary degeneration, and in glial cells accumulating abnormal tau, in AD, PiD, PSP and CBD. Double-labeling immunohistochemistry disclosed partial co-localization of SAPK/JNK-P and either MAPK/ERK-P or p-38-P immunoreactivity. These findings indicate that MAPK/ERK-P, SAPK/JNK-P and p-38-P are differentially expressed in association with tau deposits in tauopathies. Finally, CaM kinase II is present in neurons but not in glial cells, thus suggesting no role of CaM kinase II in tau phosphorylation of glial cells. These observations, together with previous results of in vitro studies, support the idea that several MAPK/ERK, SAPK/JNK, p38 and CaM kinase II may participate in tau phosphorylation in tauopathies. Lack of co-localization between MAPK/ERK-P, SAPK/JNK-P and p-38-P over-expression, and staining with the method of in situ end-labeling of nuclear DNA fragmentation in individual cells indicate that over-expression of these kinases is not linked with increased nuclear DNA vulnerability in AD, PiD, PSP and CBD.
195 citations
TL;DR: There was a significant delay in the time course of ROS-generation in brain cells from old mice and a potential model is envisaged that integrates several divergent findings described in the literature about the role of oxidative stress in brain aging.
Abstract: The objective of this study was to determine the specific relationship between brain aging and changes in the level of oxidative stress, lipid peroxidation (LPO) and in the activities of antioxidant enzymes. We used four different age groups (2-3 months, 10-11 months, 16-17 months and 20-21 months) which represented young adults, adults, beginning senescence and senescence, respectively. Basal levels of LPO products measured as malondialdehyde increased gradually with age in mouse brain homogenate. The extent of stimulated LPO products, however, was clearly decreased in the brain of adult mice compared to young mice but increased again in the brain of senescent mice. We could not detect any appreciable age-related changes in the basal as well as in stimulated levels of ROS measured with the fluorescent dyes dichlorofluorescein and dihydrorhodamine123. Nevertheless, there was a significant delay in the time course of ROS-generation in brain cells from old mice. The activities of the antioxidant enzymes CuZn-superoxide dismutase and glutathione reductase increased with age whereas glutathione peroxidase remained unchanged. On the basis of our present findings, we envisage a potential model that integrates several divergent findings described in the literature about the role of oxidative stress in brain aging.
191 citations
TL;DR: Results show that MAPKs are differentially regulated in neurons with α-synuclein-related inclusions and in neuron with abnormal tau deposits in DLB, which suggest a pathogenesis of brain stem and cortical LBs in LB diseases.
Abstract: The expression of mitogen-activated protein kinases, extracellular signal-regulated kinases (MAPK/ERK), stress-activated protein kinases, c-Jun N-terminal kinases (SAPK/JNK), and p38 kinases is examined in Parkinson disease (PD), in Dementia with Lewy bodies (DLB), covering common and pure forms, and in age-matched controls. The study is geared to gaining understanding about the involvement of these kinases in the pathogenesis of Lewy bodies (LBs) and associated tau deposits in Alzheimer changes in the common form of DLB. Active, phosphorylation dependent MAPK (MAPK-P) is found as granular cytoplasmic inclusions in a subset of cortical neurons bearing abnormal tau deposits in common forms of DLB. Phosphorylated p-38 (p-38-P) decorates neurons with neurofibrillary tangles and dystrophic neurites of senile plaques in common forms of DLB. Phosphorylated SAPK/JNK (SAPK/JNK-P) expression occurs in cortical neurons with neurofibrillary tangles in the common form of DLB. Lewy bodies (LBs) in the brain stem of PD and DLB are stained with anti-ERK-2 antibodies, but they are not recognized by MAPK-P, SAPK/JNK-P and p-38-P. Yet MAPK-P, p-38-P and SAPK/JNK-P immunoreactivity is found in cytoplasmic granules in the vicinity of LBs or in association with irregular-shaped or diffuse alpha-synuclein deposits in a small percentage of neurons, not containing phosphorylated tau, of the brain stem in PD and DLB. MAPK-P, p-38-P and SAPK-P are not expressed in cortical LBs or in cortical neurons with alpha-synuclein-only inclusions in DLB. MAPK-P, p-38-P and SAPK/JNK-P are not expressed in alpha-synuclein-positive neurites (Lewy neurites) in PD and DLB as revealed by double-labeling immunohistochemistry. These results show that MAPKs are differentially regulated in neurons with alpha-synuclein-related inclusions and in neurons with abnormal tau deposits in DLB. Moreover, different kinase expression in brain stem and cortical LBs suggest a pathogenesis of brain stem and cortical LBs in LB diseases. Finally, no relationship has been observed between MAPK-P, p-38-P and SAPK/JNK-P expression and increased nuclear DNA vulnerability, as revealed with the method of in situ end-labeling of nuclear DNA fragmentation, and active, cleaved caspase-3 expression in neurons and glial cells in the substantia nigra in PD and DLB.
155 citations
TL;DR: Rasagiline and selegiline at the dosages employed equally protect against MPTP-toxicity in the common marmoset, suggesting that selegisiline-derived metabolites are not important for the neuroprotective effects of high dose seLegiline in the non-human MP TP-primate model in the experimental design employed.
Abstract: The neurotoxin 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) has been shown to induce parkinsonism in man and non-human primates. Monoamine-oxidase B (MAO-B) has been reported to be implicated in both MPTP-induced parkinsonism and Parkinson's disease, since selegiline (L-deprenyl), an irreversible MAO-B inhibitor, prevents MPTP-induced neurotoxicity in numerous species including mice, goldfish and drosophyla. However, one disadvantage of this substance relates to its metabolism to (-)-methamphetamine and (-)-amphetamine. Rasagiline (R-(+)-N-propyl-1-aminoindane) is a novel irrevesible MAO-B-inhibitor, which is not metabolized to metamphetamine and/or amphetamine. The present study compared the effects of high doses of selegiline and rasagiline (10 mg/kg body weight s.c.) on MPTP-induced dopaminergic neurotoxicity in a non-human primate (Callithrix jacchus) model of PD. Groups of four monkeys were assigned to the following six experimental groups: Group I: Saline, Group II: Selegiline/Saline, Group III: Rasagiline/Saline, Group IV: MPTP/Saline, Group V: Rasagiline/MPTP, Group VI: Selegiline/MPTP. Daily treatment with MAO-B-inhibitors (either rasagiline or selegiline, 10 mg/kg body weight s.c.) was initiated four days prior to MPTP-exposure (MPTP-HCl, 2 mg/kg body weight subcutaneously, separated by an interval of 24 hours for a total of four days) and was continued until the end of the experiment, i.e. 7 days after the cessation of the MPTP-injections, when animals were sacrificed. MPTP-treatment caused distinct behavioural, histological, and biochemical alterations: 1. significant reduction of motor activity assessed by clinical rating and by computerized locomotor activity measurements; 2. substantial loss (approx. 40%) of dopaminergic (tyrosine-hydroxylase-positive) cells in the substantia nigra, pars compacta; and 3. putaminal dopamine depletion of 98% and its metabolites DOPAC (88%) and HVA (96%). Treatment with either rasagiline or selegiline markedly attenuated the neurotoxic effects of MPTP at the behavioural, histological, and at the biochemical levels. There were no significant differences between rasagiline/MPTP and selegiline/MPTP-treated animals in respect to signs of motor impairment, the number of dopaminergic cells in the substantia nigra, and striatal dopamine levels. As expected, both inhibitors decreased the metabolism of dopamine, leading to reduced levels of HVA and DOPAC (by >95% and 45% respectively). In conclusion, rasagiline and selegiline at the dosages employed equally protect against MPTP-toxicity in the common marmoset, suggesting that selegiline-derived metabolites are not important for the neuroprotective effects of high dose selegiline in the non-human MPTP-primate model in the experimental design employed. However, unexpectedly, high dose treatment with both MAO-inhibitors caused a decrease of the cell sizes of nigral tyrosine hydroxylase positive neurons. It remains to be determined, if this histological observation represents potential adverse effects of high dose treatment with monoamine oxidase inhibitors.
128 citations
TL;DR: Antioxidant profiles of PD patients showed characteristics overlapping with DAT and with VD, suggesting biochemical similarities between them, suggesting an association between oxidative stress and PD.
Abstract: Antioxidant profiles in Parkinson's disease (PD; n = 15), dementias of Alzheimer's type (DAT; 18) and Vascular (VD; 15), and control subjects (C; 14) were studied. Cu-Zn superoxide dismutase (SOD), catalase (CAT), glutathione system (GLU) and thiobarbituric acid reactive substances (TBARS) were measured in erythrocytes; antioxidant capacity (TRAP) in plasma. Biochemical variables were analyzed simultaneously using multi-variate and non-parametric methods. Clinical diagnostic resulted associated with the main source of variability in antioxidant variables (Kruskal-Wallis: H = 32.58, p = 0.000001). Comparison of PD and C resulted highly significant (z = 4.47, p = 0.000047), demonstrating an association between oxidative stress and PD. SOD and TBARS were significantly higher in pathological groups against C (p = 0.0000001, p = 0.051); TRAP resulted lower (p = 0.00015). Discriminant functions constructed using biochemical variables separated pathological groups (93% success) from C, and DAT (88.9%) from VD (73.3%); but not PD from DAT or VD. Antioxidant profiles of PD patients showed characteristics overlapping with DAT (60%) and with VD (40%), suggesting biochemical similarities between them.
117 citations
TL;DR: This work seems to link the outward-directed aggression of psychopathy to serotonergic hypofunctioning and high dopamine turnover, which might account for disinhibition of destructive impulses.
Abstract: Low serotonin activity in man has been related to impulsive, self-destructive violence but not to instrumental aggression aimed at dominance. A relationship has also been suggested between aggression and high catecholaminergic activity. Several studies have reported signs of aberrant dopaminergic function in attention deficit hyperactivity disorder, autism, and schizophrenia. In 22 violent offenders undergoing pretrial forensic psychiatric investigation, interpersonal and behavioral features of psychopathy, measured by the Psychopathy Checklist Revised (PCL-R), were significantly predicted by low cerebrospinal fluid (CSF) concentrations of 5-HIAA and high CSF concentrations of HVA in multivariate regression models. CSF concentrations of MHPG did not contribute to the model. This seems to link the outward-directed aggression of psychopathy to serotonergic hypofunctioning and high dopamine turnover, which might account for disinhibition of destructive impulses.
116 citations
TL;DR: Therapy with an ergot and a non-ergot dopamine agonist and levodopa confers an increased risk of excessive daytime sleepiness and secondary "sleep attacks" in Parkinson's disease (PD).
Abstract: Objective. To determine if therapy with an ergot and a non-ergot dopamine agonist and levodopa confers an increased risk of excessive daytime sleepiness and secondary "sleep attacks" in Parkinson's disease (PD).
Methods. Comparative study of three clinical groups taking, pramipexole (Group 1, n = 19, 8 monotherapy), cabergoline (Group 2, n = 22, 10 monotherapy), and levodopa monotherapy (Group 3, n = 14). Clinical and demographic characteristics, occurrence of "sleep attacks", and assessment of daytime sleepiness [using the Epworth Sleepiness Scale (ESS)], recorded.
Results. No patients reported "sleep attacks". Mean ESS scores: Group 1 (pramipexole) 8.0 ± 4.5 (range 0–16), Group 2 (cabergoline) 8.1 ± 3.9 (range 0–19), Group 3 (levodopa), 8.1 ± 5.5 (range 1–18). There was no significant difference between groups (p = 0.897). Scores of ≥16 indicating excessive daytime sleepiness (EDS) were evenly distributed throughout treatment groups, particularly in older patients with more advanced disease. Conclusions.
110 citations
TL;DR: Data support a specific alteration of CP transport function in AD patients, and CSF folate levels measured in 126 patients, including 30 AD consecutive patients to evaluate whether CP functions of folate-transport were impaired.
Abstract: Folates are involved in the cerebral metabolism of cobalamine, methionine, L-tyrosine and acetylcholine. Remarkably CSF-folate levels are 3 to 4 times higher than blood-folate levels. To reach the brain, folates are actively transported by choroid plexus (CP) as well as vitamins B6, B12, C and E. Epithelial atrophy having been reported in aging and in Alzheimer's disease (AD), we measured the CSF folate-levels of 126 patients, including 30 AD consecutive patients to evaluate whether CP functions of folate-transport were impaired. CSF-folate concentrations did not vary with age (10.47 +/- 1.93ng/ml between 20 and 60 years; 9.96 +/- 2.01 ng/ml in elderly control patients older than 60 years of age, p > 0.05) while late-onset AD patients had significantly lower CSF-folate levels (8.26 +/- 1.82 ng/ml, p < 0.001). These data support a specific alteration of CP transport function in AD patients.
TL;DR: The findings indicate that [123I]FP-CIT SPECT seems to be a useful tool to investigate the progression of dopaminergic degeneration in PD and may provide an objective method of measuring the effectiveness of neuroprotective therapies.
Abstract: We investigated the applicability [123I]FP-CIT SPECT for the assessment of the rate of dopaminergic degeneration in PD. Twenty early-stage PD patients (age range 43–73 yr; mean age 55.4) were examined twice, a mean of 12 months apart. The mean annual change in the ratio of specific to nonspecific [123I]FP-CIT binding to the striatum was used as the outcome measure. The mean annual decrease in striatal [123I]FP-CIT binding ratios was found to be about 8% (of the baseline mean). In order to demonstrate a significant effect (p < 0.05) of putative neuroprotective agent with 0.80 power and 50% of predicted protection within 2 years, 36 patients are required in each group, when the effects are measured by means of changes in [123I]FP-CIT binding ratios in whole striatum. Our findings indicate that [123I]FP-CIT SPECT seems to be a useful tool to investigate the progression of dopaminergic degeneration in PD and may provide an objective method of measuring the effectiveness of neuroprotective therapies.
TL;DR: It is demonstrated, that 24-hydroxycholesterol-induced neurotoxicity in differentiated SH-SY5Y cells was due to apoptosis, as indicated by DNA-fragmentation, caspase-3 activation and a decrease of the mitochondrial membrane potential.
Abstract: 24-Hydroxycholesterol, the main cholesterol elimination product of the brain is increased in serum of Alzheimer patients. This oxysterol behaves neurotoxic towards the human neuroblastoma cell line, SH-SY5Y. Here we demonstrate, that 24-hydroxycholesterol-induced neurotoxicity in differentiated SH-SY5Y cells was due to apoptosis, as indicated by DNA-fragmentation, caspase-3 activation and a decrease of the mitochondrial membrane potential. Free radicals were generated, resulting in the death of 75% of the cells within 48 h; neurotoxicity in differentiated SH-SY5Y cells was partially prevented by physiological concentrations of vitamin E (50–100 μM) in that 75% of the cells survived. Physiological concentrations of estradiol-17β (1–100 nM) elicited a protective effect in differentiated cells, which was not significant; however, in undifferentiated cells a significant protection was noted by this steroid hormone. Vitamin C and melatonin did not prevent 24-hydroxycholesterol-induced neurotoxicity. These in vitro data support the in vivo observed beneficial effects reported as circumstantial evidence of vitamin E and estradiol-17β treatment in the prevention and therapy of neurodegenerative disease.
TL;DR: Melatonin up-regulated the level of gene expression of transforming growth factor-β (TGF-β), macrophage-colony stimulating factor (M-CSF), tumor necrosis factor-α (TNF-α) and stem cell factor (SCF) in PEC, and thelevel of gene Expression in splenocytes was analyzed with the reverse transcription-polymerase chain reaction (RT-PCR).
Abstract: Male C57 mice received 10 consecutive daily intraperitoneal injections of melatonin, 5-methoxytryptamine or 5-methoxytryptophol (5mg/kg body weight). Control mice received the alcoholic saline vehicle. All mice were sacrificed 24 hours after the last injection. Following extraction of RNA from peritoneal exudate cells (PEC) and splenocytes, the level of gene expression was analyzed with the reverse transcription-polymerase chain reaction (RT-PCR). The results revealed that melatonin up-regulated the level of gene expression of transforming growth factor-beta (TGF-beta), macrophage-colony stimulating factor (M-CSF), tumor necrosis factor-alpha (TNF-alpha) and stem cell factor (SCF) in PEC, and the level of gene expression of interleukin-1beta (IL-1beta), M-CSF, TNF-alpha, interferon-gamma (IFN-gamma) and SCF in splenocytes. 5-Methoxytryptamine augmented the level of gene expression of TGF-beta, M-CSF and SCF in PEC, and the level of gene expression of IL-1beta, TNF-alpha, IFN-gamma, M-CSF and SCF in splenocytes. 5-Methoxytryptophol elevated the level of gene expression of TNF-alpha, IL-1beta, TGF-beta and M-CSF in PEC, and the level of gene expression of inducible nitric oxide synthase (iNOS), IL-1beta, M-CSF, TNF-alpha, IFN-gamma and SCF in splenocytes.
TL;DR: It is concluded that ChEIs have a beneficial effect on the cognitive state of PDD patients without aggravating motor function.
Abstract: Patients suffering from Parkinson's disease (PD), often develop dementia (PDD). Their brain histology reveals Alzheimer's disease (AD) like changes and decreased cholin-acetyl transferase (ChAT) activity, in addition to typical PD changes. This cholinergic deficiency has been related to the degree of mental decline. As centrally acting cholinesterase inhibitors (ChEIs) provide cognitive and non-cognitive improvement for AD patients, the same therapeutic effect was hypothesized for PDD patients as well. The goal of this study was to assess the effect of ChEIs on both the cognitive and motor state of PDD patients. An open study was conducted. Eleven consecutive PDD patients (M/F 6/5 mean age 75 y) were found eligible for inclusion. They were treated for 26 weeks with tacrine (7 patients) and donepezil (4 patients) as add-on to their regular anti PD drugs. Cognitive assessment was performed at baseline and endpoint by Mini-Mental-State-Examination (MMSE) and Alzheimer's-Disease-Assessment-Scale (ADAS-cog). Global Deterioration Scale (GDS) was performed to evaluate active daily living (ADL). Motor evaluation was performed using Short Parkinson Evaluation Scale (SPES) at baseline and end-point. Statistical analysis used Student's paired t-test, ANOVA with repeated measures and Pearson correlation coefficient. ChEIs treated PDD patients showed improvement in their cognitive state. Mean ADAS-cog improved significantly by 3.2 points (p < 0.012). Mean MMSE and GDS improved non-significantly by 1.2 and 0.2 points respectively. There was no change in motor function as evident by mean SPES scores, 16.5 at baseline and endpoint. Five individuals actually demonstrated motor improvement under ChEIs. We conclude that ChEIs have a beneficial effect on the cognitive state of PDD patients without aggravating motor function.
TL;DR: The results suggest that the amnesic and anxiogenic effects of chronic infusion of β-amyloid are related to the decreased acetylcholine release and reduced PKC activation.
Abstract: In the present study we found that chronic infusion of β-amyloid fragment (25–35) at nanomolar concentration into rat cerebral ventricle impairs learning and memory. At a concentration of 3 nmol/day but not 0.3 nmol/day, β-amyloid significantly reduced the spontaneous alternation behavior and the memory performance in the water maze and multiple passive avoidance tests. A significant increase in anxiety was also found in the animals infused with 3 nmol/day β-amyloid fragment. Memory deficits and the increased emotionality were correlated with a decreased nicotine-evoked acetylcholine release from the frontal cortex/hippocampus, as assessed by microdialysis, in freely moving rats. The amyloid fragment infused either at pico- or nanomolar concentrations reduced the affinity of [3H] phorbol dibutyrate binding, an index of activated protein kinase C (PKC), and increased the total number of binding sites in the hippocampal particulate fraction. Our results suggest that the amnesic and anxiogenic effects of chronic infusion of β-amyloid (25–35) are related to the decreased acetylcholine release and reduced PKC activation.
TL;DR: Assessment of changes of susceptibility to apoptotic cell death by oxidative stress in aging and its inhibition by the antioxidant Ginkgo biloba extract EGb761 found ROS-induced apoptosis was significantly reduced in the EGb 761 group, Interestingly, this effect seemed to be more pronounced in old mice.
Abstract: Enhanced apoptosis and elevated levels of reactive oxygen species (ROS) play a major role in aging. In addition, several neurodegenerative diseases are associated with increased oxidative stress and apoptosis in neuronal tissue. Antioxidative treatment has neuro-protective effects. The aim of the present study was to evaluate changes of susceptibility to apoptotic cell death by oxidative stress in aging and its inhibition by the antioxidant Ginkgo biloba extract EGb761. We investigated basal and ROS-induced levels of apoptotic lymphocytes derived from the spleen in young (3 months) and old (24 months) mice. ROS were induced by 2-deoxy-D-ribose (dRib) that depletes the intracellular pool of reduced glutathione. Lymphocytes from aged mice accumulate apoptotic cells to a significantly higher extent under basal conditions compared to cells from young mice. Treatment with dRib enhanced this difference, implicating a higher sensitivity to ROS in aging. Apoptosis can be reduced in vitro by treatment with EGb761. In addition, mice were treated daily with 100 mg/kg EGb761 per os over a period of two weeks. ROS-induced apoptosis was significantly reduced in the EGb761 group. Interestingly, this effect seemed to be more pronounced in old mice.
TL;DR: Although one can no longer expect that 2 of 3 depressed patients will respond to treatment, the newer antidepressants are better tolerated, because they produce less anticholinergic side effects.
Abstract: Iproniazid and imipramine, the prototypes of monoamine oxidase inhibitor (MAOI) and monoamine (re)uptake inhibitor (MAUI) antidepressants, were introduced in 1957. The relationship between iproniazid's antidepressant effect and its MAO inhibiting property was tenuous. Because of the potential drug-drug interactions and the need for dietary restrictions, the use of MAOIs became restricted to atypical depression. The confounding of reserpine reversal with antidepressant effect led to the theory that MAU inhibition is responsible for imipramine's antidepressant effect. Driven by neuropharmacological theory, non-selective reuptake inhibitors were replaced first by selective norepinephrine reuptake inhibitors, then by selective serotonin reuptake inhibitors, and more recently, by a series of new antidepressants to relieve the stimulation of serotonin-5HT2A receptors and the compensatory decline of dopamine in the brain. Each antidepressant has its own identity, but meta-analyses indicate a widening of the antidepressant response range from 65-70% to 45-79%, and a lowering of the antidepressant threshold from 65% to 45%. Although one can no longer expect that 2 of 3 depressed patients will respond to treatment, the newer antidepressants are better tolerated, because they produce less anticholinergic side effects.
TL;DR: Findings ascertain an anti-apoptotic effect of the peptide fraction of Cerebrolysin and reveal a transient viability promotingEffect of the amino acid fraction, which is most likely due to improved nutritional supply.
Abstract: Cerebrolysin (EBEWE Arzneimittel, Austria, Europe) is a widely used drug relieving the symptoms of a variety of neurological disorders, particularly of neurodegenerative dementia of the Alzheimer's type. It consists of approximately 25% of low molecular weight peptides (<10k DA) and a mixture of approximately 75% free amino acids, this being based on the total nitrogen content. In this study we used a low serum (2% serum supplement) cell stress in-vitro model to assess drug effectiveness on neuronal viability and programmed cell death (PCD). In this in-vitro model the type of cell death was previously shown to be primarly apoptotic, which was verified by DNA-laddering and TUNEL-staining. For evaluation of neuronal viability a MTT-reduction assay was performed after 4 DIV and 8 DIV and the percentage of apoptotic neurons was determined by bis-benzimide staining of nuclear chromatin. To differentiate between possible effects of the free amino acids and the peptide fraction of Cerebrolysin an artificial amino acid mixture (AA-mix) was used as a control. Cerebrolysin, the AA-mix and 10% foetal calf serum (FCS) caused a similar increase in viability after 4 DIV, whereas the effects of the growth factors BDNF and FGF-2 were less pronounced. After 8 DIV Cerebrolysin, but not the AA-mix, was able to ameliorate neuronal viability, which could reflect a neuro-protective effect or an increased activity of the mitochondrial dehydrogenase measured in a MTT-reduction assay. The percentage of cells showing apoptotic chromatin changes was significantly reduced (p < 0.01) in cultures treated with Cerebrolysin, whereas the AA-mix failed to decrease the percentage of cells showing apoptotic chromatin changes. These findings ascertain an anti-apoptotic effect of the peptide fraction of Cerebrolysin and reveal a transient viability promoting effect of the amino acid fraction, which is most likely due to improved nutritional supply.
TL;DR: In this article, the authors studied eight clinically non-demented PD patients and ten age-matched controls with serial volumetric T1-weighted MRI and found significant correlations between reductions in percentage brain volume loss and estimated reductions in performance IQ.
Abstract: We studied eight clinically non-demented PD patients and ten age-matched controls with serial volumetric T1-weighted MRI. All PD patients underwent full neuropsychological testing at baseline and follow up scans. Sub-voxel coregistration of the serial MRI scans with quantification of changes in total brain substance and ventricular size per year was performed. The PD patients had significant reductions in both percentage and absolute annual brain volume loss when compared to age-matched controls (p < 0.001). There were significant correlations between reductions in percentage brain volume loss and estimated reductions in performance IQ (r = 0.841, p = 0.004) and full scale IQ (r = 0.63, p = 0.049), measured by subtracting IQ measures at time of follow up scan from premorbid estimates. In conclusion, PD patients have a significant rate of median brain volume loss [10.35 (range) 6.69-16.90 ml/year] with no significant loss seen in age-matched controls, and these changes correlate with global measures of cognitive decline. Further longitudinal studies could evaluate whether serial volumetric MRI is a useful technique in predicting the preclinical onset of dementia in Parkinson's disease patients, and its role in the assessment of putative treatments for slowing disease progression.
TL;DR: The existence of an "addiction memory" (AM) and its importance in relapse occurrence and maintenance of learned addictive behaviour will be explained with neurobiological and clinical arguments and is compatible with recently discussed results of neurosciences.
Abstract: The existence of an "addiction memory" (AM) and its importance in relapse occurrence and maintenance of learned addictive behaviour will be explained with neurobiological and clinical arguments. Because the human brain is an open learning system, which reveals its own neuronal connectivity through the experience of the perceived environment with its own state, the personal AM is interpreted as an individual acquired software disturbance in relation to selectively integrating "feedback loops" and "comparator systems" of neuronal information processing. This is in accordance with the experience that the AM and its specific cue reactivity can be activated at any time by relapse-endangering complex internal and/or external situations with cue stimulated craving. The AM becomes part of the personality represented on the molecular level via the neuronal level and the neuropsychological level, especially in the episodic memory. This neurobiological unchangeable imprinted addictive behaviour with "loss of control" and "obsessive-compulsive craving" was also found in a long-term learning model with rats (Wolffgramm). Identical homological phylogenetically old brain structures for learning mechanisms allow the comparison between human and animal behaviour. The AM seems to be a clinical-empirical proved reality. It is compatible with recently discussed results of neurosciences.
TL;DR: The present data indicate that the increase of the density of brain D-1 and 5HT-2A receptors of rats subjected to CUS might be involved in the pathophysiology of "animal depression" (since chronic antidepressant treatment produced opposite changes i.e. decrease in thedensity of these receptors) and thus in pathophysiological of human depression.
Abstract: Antidepressant drugs are devoid of mood-elevating effects in normal (non-depressed) human subjects, thus, it is necessary to evaluate the antidepressant property of compounds (drugs) in animal models of depression. Several animal models of depression have been introduced, however, only a few have been extensively validated. In the present study we report the results of investigations into monoaminergic receptors in the brain of rats subjected to chronic unpredictable stress (CUS) procedure (one of the well validated animal models of depression). We have examined the dopaminergic (D-1, D-2), adrenergic (α-1, β-1) and serotonergic (5HT-1A, 5HT-2A) receptors in different brain regions by a saturation radioligand binding method in rats subjected to CUS paradigm and control animals. CUS procedure resulted in a significant 29% increase in the D-1 receptor density in the limbic system and 52% increase of the density of 5HT-2A receptors in the cerebral cortex. The present data indicate that the increase of the density of brain D-1 and 5HT-2A receptors of rats subjected to CUS might be involved in the pathophysiology of "animal depression" (since chronic antidepressant treatment produced opposite changes i.e. decrease in the density of these receptors) and thus in pathophysiology of human depression.
TL;DR: The results of this study highlight the role of the DLPFC blood flow impairment in the pathogenesis of ADHD even in young subjects without structural abnormalities.
Abstract: Recent studies suggest a role for prefrontal cortex abnormalities in the pathogenesis of attention deficit/hyperactivity disorder (ADHD). We evaluated young drug-naive ADHD outpatients without MRI structural abnormalities to detect prefrontal cortex regional cerebral blood flow (rCBF) functional dysregulation; correlation between age and rCBF; and correlation between symptoms profile and rCBF. Functional brain activities (i.e. rCBF), neuropsychological attention performance and symptom profile were evaluated respectively by single photon emission computerized tomography (SPECT) scan, Stroop Test and the Child Attention Problem Rating Scale. There was a decreased rCBF in the left dorso lateral prefrontal cortex (DLPFC) compared to the right DLPFC of the subjects. In addition, there were positive correlations between age and relative rCBFs of the dorsolateral and orbital prefrontal cortex, and negative correlations between age and absolute rCBFs of the dorsolateral and orbital prefrontal cortex. Finally, higher levels of right relative rCBF and lower levels of left relative rCBF were predictors of higher severity of clinical symptom expression and neuropsychological attention impairment. The results of this study highlight the role of the DLPFC blood flow impairment in the pathogenesis of ADHD even in young subjects without structural abnormalities.
TL;DR: A reduction of dopamine transporter immunoreactivity in PBL in the early clinical stages of Parkinson's disease is demonstrated, contributing to the understanding of the peripheral dopamine system in PD.
Abstract: There is increasing interest in the identification of biological markers for the early diagnosis of Parkinson's disease (PD). Previous studies indicate changes of dopamine content, tyrosine hydroxylase immunoreactivity and dopamine receptors in peripheral blood lymphocytes (PBL) in PD. Here we demonstrate a reduction of dopamine transporter immunoreactivity in PBL in the early clinical stages of the disease. These findings contribute to our understanding of the peripheral dopamine system in PD.
TL;DR: In conclusion, NIP differs from PD for more bilateral involvement with relative symmetry, and by affecting upper limbs more often than the lower ones, while PD tends to involve gait and posture more often.
Abstract: In order to characterize the clinical spectrum of neuroleptic-induced parkinsonism (NIP), we studied a population of consecutive psychiatric in-patients treated with neuroleptics for at least two weeks, who were diagnosed by their psychiatrist as having parkinsonism. Parkinsonism was confirmed by a movement disorders specialist who performed neurological assessment including the motor examination and the activities of daily living (ADL) sections of the Unified Parkinson's Disease Rating Scale (UPDRS), and the Hoehn and Yahr (H&Y) staging. Seventy-five patients (54 males), aged 46 ± 13 years (range 21 to 73 years) were included in the analysis. The mean duration of neuroleptic therapy was 15 ± 12 years, while 61% were treated for more than 10 years. Most of the patients (n = 66, 88%) were scored as H&Y stage 2.5 or less. Rest tremor was present in 44% of the patients, and usually persisted in action. Forty-one patients (61%) had symmetrical involvement. Parkinsonian signs were significantly more common and pronounced in the upper in comparison with the lower limbs (p = 0.0001). Gait disturbances were mild and freezing of gait was very rare (n = 2). Neither age nor duration of therapy or their interaction affected the total motor score or any of the motor sub-scores. In conclusion, NIP differs from PD for more bilateral involvement with relative symmetry, and by affecting upper limbs more often than the lower ones. NIP tends to be associated with the triad of bradykinesia, tremor and rigidity while PD tends to involve gait and posture more often. NIP develops unrelated to duration of neuroleptic treatment or age of the patient, suggesting an individual predisposition to blockage of the dopaminergic receptors.
TL;DR: The data suggest that tremor in PD is generated by multiple oscillatory circuits, which operate on similar frequencies.
Abstract: Recent evidence points to involvement of central nervous system oscillators in Parkinson's disease (PD) rest tremor. It remains unknown whether one or multiple oscillators cause tremor in multiple limbs. Based on the prediction that multiple oscillators would cause low coherence even with similar average frequency, we studied 22 PD patients using accelerometers on multiple limbs. Records were digitized and spectral analysis was performed. Peak frequencies in the arms, legs, and chin were similar, indicating that biomechanical factors did not determine the frequency. Coherence between different axes of individual accelerometers and between different segments of the same limb was high. However, coherence between tremor in different limbs was low. There was no consistent pattern across patients of ipsi- vs. contralateral predominance of coherence. These data suggest that tremor in PD is generated by multiple oscillatory circuits, which operate on similar frequencies.
TL;DR: The results suggest that mitochondria play a key role in the induction of apoptosis by the neurotoxin and the prevention by aliphatic propargylamines.
Abstract: Endogenous N-methyl(R)salsolinol, which caused parkinsonism in rats by injection in the striatum, was found to induce apoptosis in dopaminergic neuroblastoma SH-SY5Y cells. After 12-h incubation with 500 μM N-methyl(R)salsolinol, almost all the cells died with apoptosis and necrotic cell death was negligible. N-Methyl(R)salsolinol was much more potent to induce apoptosis than the (S)-enantiomer. The mechanism of apoptosis was studied in relation to changes in mitochondrial membrane potential, ΔΨm, using a fluorescent indicator, JC-1. Red fluorescence of J-aggregates representing hyperpolarized ΔΨm was found to decrease significantly within 60 min after incubation with N-methyl(R)salsolinol, but not by the (S)-enantiomer at the same concentration. It suggests that mitochondria may recognize the stereo-chemical structure of N-methyl(R)salsolinol. Aliphatic propargylamines, (R)-N-(2-heptyl)-N-methylpropargyl-amine and (R)-N-(2-heptyl)propargylamine, were found to prevent ΔΨm loss and subsequent apoptosis induced by N-methyl(R)salsolinol. These results suggest that mitochondria play a key role in the induction of apoptosis by the neurotoxin and the prevention by aliphatic propargylamines.
TL;DR: Hypoglutamatergic mice show defective habituation, impaired attention, a meagre behavioural repertoire and a general behavioural primitivization, and it was found that each receptor antagonist had a unique effect on the MK-801-induced behavioural primItivization.
Abstract: In a hypoglutamatergic rodent model, we have observed certain behaviours that might have relevance for the cognitive impairments seen in autism and schizophrenia. Thus, hypoglutamatergic mice show defective habituation, impaired attention, a meagre behavioural repertoire and a general behavioural primitivization. The aim of the present study was to characterise and quantify changes in movement pattern in mice rendered hypoglutamatergic by means of MK-801 treatment, using an automated video tracking system. Further, the effects of four different antipsychotic drugs, the classical neuroleptic haloperidol, the atypical antipsychotic clozapine, the DA D2/5-HT2A antagonist risperidone and the selective 5-HT2A-receptor antagonist M100907, were compared with respect to effects on NMDA antagonist-induced movement pattern alterations. We found that each receptor antagonist had a unique effect on the MK-801-induced behavioural primitivization. Haloperidol was unable to affect the monotonous behaviour induced by MK-801, while risperidone, clozapine and M100907 produced movement patterns of high intricacy.
TL;DR: This work has compared the effects of transient and permanent middle cerebral artery occlusion (MCAO) on the infarct volume, and examined whether a selective α2-adrenergic receptor agonist, dexmedetomidine, is able to reduce ischemic damage after transient or permanent MCAO in rats.
Abstract: Increased sympathetic tone is a consequence of cerebral ischemia. Although the role of catecholamines in ischemic damage is still unclear, in some experimental ischemia models α2-adrenergic agonism has proved to be neuroprotective. In the present work we have compared the effects of transient and permanent middle cerebral artery occlusion (MCAO) on the infarct volume, and, also, examined whether a selective α2-adrenergic receptor agonist, dexmedetomidine (9 μg/kg or 15 μg/kg i.v.), is able to reduce ischemic damage after transient or permanent MCAO in rats. Permanent MCAO led to a significantly larger infarct volume than transient occlusion (p < 0.05). The rats receiving the higher dose of dexmedetomidine were detectected to have smaller (statistically non-significant) infarct volume in the cortex (30.9%) and in the striatum (20.3%) after transient occlusion. Additionally, dexmedetomidine caused significant variations in the physiological parameters.
TL;DR: The differences in qEEG in patients with different stages of dementia under donepezil treatment may be related to different compensatory capacities due to structural and functional brain disturbances.
Abstract: In this pilot study, we examined the long-term treatment effect of donepezil on the quantitative EEG (qEEG) in 12 Alzheimer's disease patients The qEEGs of the mean absolute and relative amplitudes of betal, alpha, theta and delta activities were obtained at baseline and during donepezil treatment Comparisons of awake qEEG prior to and during treatment were performed using a 2-way analysis of variance (ANOVA) with repeated measures In patients with mild dementia (n = 5), the qEEG analysis showed a significant reduction of the mean absolute theta activity (p = 005) by donepezil, particularly in frontal and temporo-parietal areas In patients with moderate/severe dementia (n = 7), a significant decrease in the mean absolute beta 1 activity (p = 002), particularly in the frontal and occipital areas may be attributed to disease progression which was not counteracted by the long-term treatment The differences in qEEG in patients with different stages of dementia under donepezil treatment may be related to different compensatory capacities due to structural and functional brain disturbances