Showing papers by "University of Cagliari published in 1978"
TL;DR: Pretreatment with diazepam, but not with pentobarbital, prevented stress-induced increased in DOPAC levels, and DA content did not change after stress in any of the structures analyzed.
294 citations
TL;DR: The results indicate that enkephalins stimulate dopamine synthesis by an action on opioid receptors localized on dopaminergic nerve terminals localized on dopamine nerve terminals.
Abstract: The intraventricular injection of methionine-enkephalin (50 to 100 micrograms) or [d-Ala2]-methionine-enkephalinamide (1.5 to 12 micrograms), a synthetic enkephalin analog resistant to enzyme degradation, caused a marked dose-dependent increase in dihydroxyphenylacetic acid and homovanillic acid concentrations in the rat striatum. The [d-Ala2] analog increased the accumulation of dopa in the striatum after aromatic amino acid decarboxylase inhibition, indicating that it increased dopamine synthesis. At the highest doses used both enkephalins failed to modify brain serotonin metabolism. The monolateral microinjection of the [d-Ala2]] analog (3 to 6 micrograms) into the caudate nucleus increased the concentration of dihydroxyphenylacetic acid in the injected side, whereas bilateral injection increased the concentration of this compound in both caudate nuclei and caused catalepsy. The stimulant effect of the [d-Ala2] analog on dopamine synthesis in the striatum persisted after destruction of striatal postsynaptic dopamine receptors with kainic acid. The biochemical and behavioral effects of enkephalins were prevented by naloxone, a specific narcotic antagonist. The results indicate that enkephalins stimulate dopamine synthesis by an action on opioid receptors localized on dopaminergic nerve terminals.
160 citations
TL;DR: The contralateral turning and the stereotypes induced by the acute, intranigral administration of muscimol were very similar to the chronic effects elicited by intranIGral kainic acid (k.a.) observed from 24 h to several days after treatment.
151 citations
TL;DR: This chapter discusses the pharmacology and neurochemistry of apomorphine, which was first employed as a powerful emetic agent and is metabolized by O-glucuronidation, O-methylation, and, probably, by N-demethylation.
Abstract: Publisher Summary This chapter discusses the pharmacology and neurochemistry of apomorphine. Apomorphine was first employed as a powerful emetic agent. Apomorphine can be obtained by the acid-catalyzed rearrangement of morphine and by total synthesis. The hydrochloride forms colorless crystals that readily undergo superficial oxidation and assume a greenish tinge. Apomorphine solutions in water are unstable, turning green upon exposure to light and to air oxygen. Oxidation of apomorphine is much slower in acidic media. These properties of apomorphine explain the current addition of ascorbic acid to apomorphine solutions. The preparation of apomorphine by the acid-catalyzed rearrangement of morphine results in the retention of the configuration at the C6a chiral center leading to the corresponding (–)-isomer. Apomorphine has been measured in biological samples by spectrophotometric and fluorimetric methods and by fluorescence quenching after chromatographic separation. Apomorphine is metabolized by O-glucuronidation, O-methylation, and, probably, by N-demethylation. Apomorphine is methylated in vitro when incubated with rat liver soluble fraction in the presence of S-adenosylmethionine as methyl donor. This reaction is carried by the enzyme COMT.
127 citations
TL;DR: Subcutaneous administration of apomorphine at the dose of 50 μg/kg to sexually experienced male rats decreased the number of penile intromissions necessary to reach ejaculation and accelerated the achievement of ejaculation, suggesting that a dopaminergic hyperactivity may be involved in premature ejaculation.
88 citations
TL;DR: The unilateral, intranigral administration of kainic acid produced a syndrome characterized by early sequelae of contra- and ipsilateral circling and by a chronic contralateral turning associated with moderate loss of neurons in the pars reticulata that may be related to dopaminergic nigro-neostriatal neuron stimulation.
86 citations
TL;DR: The results indicate that behavioural responses elicited by striatal DA-receptor stimulation are effected through a GABA-mediated inhibition of pars reticulata neurons.
85 citations
TL;DR: The results suggest that enkephalins may play a role in the regulation of copulatory behavior in sexually experienced male rats paired with receptive females.
71 citations
68 citations
TL;DR: The data indicate that in prepubertal obesity, maturation of adrenal gland function (chiefly the delta 5 pathway), is notably enhanced, whereas gonadal secretion of estradiol is impaired in the presence of high levels of FSH and PRL.
Abstract: Plasma levels of gonadotropins, PRL, T4, and adrenal and gonadal steroids were measured in two groups of 7- to 9-yr-old and 10- to 11-yr-old obese prepubertal girls, and were compared to those found in groups of nonobese girls of the same age. The data found in normal weight subjects confirm the data reported in the literature, showing a significant rise between the 7- to 9- and 10- to 11-yr groups, of FSH, pregnenolone, dehydroepiandrosterone, testosterone, and estradiol plasma levels, while LH, PRL, T4, cortisol, progesterone, 17-hydroxyprogesterone (17P), and androstenedione remained constant. In the obese subjects, pregnenolone and dehydroepiandrosterone levels are notably higher than in the normal girls, in the same range as those found in adult women; furthermore, they show no rise between the two age groups. The obese prepubertal groups had significantly higher progesterone, androstenedione, and PRL levels in comparison with those observed in girls of normal weight, but 17- hydroxyprogesterone, cor...
63 citations
TL;DR: Research was carried out on fertile and sterile cysts of Echinococcus granulosus taken from hosts of different species and there seems to be a direct correlation between cyst development and laminar layer thickness, whereas no correlations emerged with the organ in which cysts are located.
TL;DR: Both gonadotrophin values were significantly lower in these P4–5 pre‐menarchal girls than those found in adult women in the early follicular phase, and no significant changes were found in plasma Prl, cortisol and 17P levels during pubertal development; in contrast, plasma concentrations of DHA tripled from P1 to P 4–5, reaching adult levels.
Abstract: SUMMARY
The peripheral venous plasma concentrations of gonadotrophins (LH and FSH), prolactin (Prl), cortisol, dehydroepiandrosterone (DHA), dehydroepiandrosterone-sulphate (DHA-S), pregnenolone (Δ5P), progesterone (P), 17-hydroxyprogesterone (17P), androstenedione (A), testosterone (T), dihydrotestosterone (DHT) and oestradiol (E2) were measured in girls at different stages of sexual development (from P1 to P4–5 according to Tanner, 1962). Both gonadotrophins increase progressively during sexual maturation, to reach the highest concentrations in P4–5. However, the FSH values were significantly lower in these P4–5 pre-menarchal girls than those found in adult women in the early follicular phase. No significant changes were found in plasma Prl, cortisol and 17P levels during pubertal development; in contrast, plasma concentrations of DHA tripled from P1 to P4–5, reaching adult levels. A progressive rise was also found in DHA-S plasma levels. A significant, but less evident increase was found in Δ5P and P plasma concentrations, from group P1 to P4–5. A, T and DHT levels rose progressively and significantly from P1–2 to the end of sexual maturation. In the case of E2, only a moderate increase was found during pubertal development.
All these data indicate that during pubertal development, there is a progressive reduction in the sensitivity towards oestrogen of the hypothalamic centres controlling gonadotrophin secretion.
Prl does not seem to be involved in human sexual maturation, while important changes have been found in adrenal androgens. The constant levels of 17P and cortisol, in comparison with the behaviour of DHA, DHA-S, T and A, seem to indicate that during this period of life, the adrenal gland is stimulated by unknown factors other than ACTH, acting on the adrenal androgen-producing cells and responsible for the reported rises in plasma adrenal androgens.
TL;DR: Haloperidol and Hspiroperidol binding studies after kainate injection into the striatum indicate the presence of dopamine receptive sites not located on post-synaptic membranes, but the physiological meaning of these “presynaptic” sites remains to be established.
TL;DR: It can be concluded that insulin stimulates the transport of large neutral amino acids from blood to brain and that the level of free serum tryptophan also controls the entry of tryPTophan into the brain under the influence of insulin.
Abstract: —
The administration of oral glucose to fasted rats produced a decline of all large neutral amino acid levels in serum, including that of the free fraction of tryptophan. In addition to this well known effect, it also decreased the brain concentrations of leucine, isoleucine and valine, while increasing those of tryptophan, tyrosine and phenylalanine. The total concentration of large neutral amino acids in serum was decreased by 44%, while it was slightly increased in brain. Analogous results were obtained in 4 rats injected with exogenous insulin. Moreover, the administration of either glucagon or isoproterenol to rats force-fed with glucose produced a decline in total serum tryptophan concentration proportional to that of the rise in FFA, while it increased free serum tryptophan and brain tryptophan levels. It can be concluded that insulin stimulates the transport of large neutral amino acids from blood to brain and that the level of free serum tryptophan also controls the entry of tryptophan into the brain under the influence of insulin.
Journal Article•
TL;DR: The localization of endogenous peroxidase was studied in human parotid and submandibular glands using the medium of Strum & Karnovsky either at pH 7 or at pH 8.3, after a short fixation of the tissues with a low concentration of glutaraldehyde.
Abstract: The localization of endogenous peroxidase was studied in human parotid and submandibular glands using the medium of Strum & Karnovsky either at pH 7 or at pH 8.3, after a short fixation of the tissues with a low concentration of glutaraldehyde. At pH 7 reaction product was found in seromucous cells of both glands in the cisternae of the rough endoplasmic reticulum, in the elements of the Golgi apparatus, and in secretory products. However, while in the parotid gland all secretory granules showed peroxidase activity, in the submandibular gland some of the granules were left unstained. At pH 8.3 the pattern of reactivity was practically unchanged in the submandibular gland, whereas the amount of precipitate noticeable in the secretory granules of the parotid gland was greatly reduced. The method of Novikoff et al. for catalase revealed the presence of a number of small bodies having in the characteristics of peroxisomes. Acid phosphatase was not demonstrable in the secretory granules of either parotid or submandibular glands. The lead precipitate indicating enzyme activity was observed only in lysosomes and, occasionally, in the elements of the Golgi apparatus of some sermucous cells.
TL;DR: In this article, the spectral response at 77 and 300 K and the photoconductivity decay at 300 K of CdIn2S4 single crystals are studied and an exponential electron trap distribution is deduced from the dependence of the response time on the excitation intensity and from the lux-ampere characteristics.
Abstract: The spectral response at 77 and 300 K and the photoconductivity decay at 300 K of CdIn2S4 single crystals are studied. Photoconductivity peaks are explained on the basis of the known optical constants and the energy position of the acceptor level is obtained. From the dependence of the response time on the excitation intensity and from the lux-ampere characteristics an exponential electron trap distribution is deduced. The very high trap density (≈ 1020 cm−3) as well as the continuous distribution are explained in terms of high disorder in the cation sublattice, probably related to the second order phase transition found by Czaja at 403 K.
On a etudie le spectre de photoconductivite a 77 et a 300 K et le temps de reponse du photocourant a 300 K dans des monocristaux de CdIn2S4. On a explique les pics observes sur la base des proprietes optiques fondamentaux et on a obtenu la position des niveaux accepteurs. De l'etude du temps de response en fonction de l'intensite d'excitation et de la courbe lux-ampere, on a deduit la presence d'une distribution exponentielle des pieges electroniques. On explique la densite tres elevee des pieges (≈ 1020 cm−3) ainsi que leur distribution continue sur la base d'un desordre important dans le sousreseau cationique, probablement relie a la transition de phase du deuxieme ordre observe par Czaja a 403 K.
TL;DR: The present method has been applied to compare the effect of different psychotropic drugs on the dopamine and DOPAC levels in the caudate nucleus, substantia nigra and medial basal hypothalamus.
Abstract: A radioenzymatic method for simultaneous determination of dopamine and DOPAC in small brain areas is described. By using this assay, 250 pg of dopamine and 150 pg of DOPAC can be estimated. The present method has been applied to compare the effect of different psychotropic drugs on the dopamine and DOPAC levels in the caudate nucleus, substantia nigra and medial basal hypothalamus.
TL;DR: The intragastric of intraperitoneal administration of metergoline stimulates dopamine synthesis in the rat and mouse brain and blocks DA-sensitive adenylate cyclase and displaces H 3 -haloperidol from specific binding sites in striatal homogenates.
TL;DR: In vitro studies show that, in the presence of air, the protein catalyses the oxidation of Fe’*, which is then incorporated into the shell, and the results indicate that 4 FeV are oxidized per oxygen molecule and that the product of oxygen reduction is water.
TL;DR: Bromocriptine is used in the treatment of parkinsonism with contrasting results and of Huntington's chorea and induces a marked decrease of cGMP levels in cerebellum while apomorphine and other dopaminergic drugs increase the levels ofcGMP.
Abstract: Ergotamine and dihydroergotamine show a higher blocking effect towards the dopamine-induced stimulation of adenylate cyclase activity than to the apomorphine-induced stimulation. This could reflect a
TL;DR: Pretreatment with para -chlorophenyl-alanine, an inhibitor of serotonin synthesis, or with methergoline, a serotonin receptor blocker, potentiated the anaesthetic and analgesic effect of ketamine.
TL;DR: MCE given by oral, intraperitoneal or subcutaneous route to reserpinized male and female rats proved to be an effective and long-lasting anti-prolactin agent.
TL;DR: In this article, electron spin resonance (ESR) studies have been made on the undiluted Cu(N-ethyl imidazole) 4 (ClO 4 ) 2 and Cu (N-propyl imidaze) 4(ClO4 ) 2 complexes in their polycrystalline forms at 295 and 77 K.
TL;DR: In this article, the π-bond orders of the thio- and seleno-ketonic links in these compounds are higher than those found for 1,3-imidazolidine-2-thione and -2-selone.
TL;DR: In this paper, the reflectivity of CdIn2S4 has been measured at 300 K and 77 K in the 2-10 eV energy range and the analysis of the low temperature data by means of the Kramers Kronig relations led to the determination of the optical constants.
TL;DR: By reacting cobalt(III) halides with N-methyl and N-ethyl, 1,3-eimidazolidine-2-thione, CoL2X2 complexes (X = Cl, Br, I) are obtained as mentioned in this paper.
TL;DR: In this paper, a bridging ligand was proposed to behave as a monodentate -NH2 and -N(ring) bonded species in polymeric complexes with octahedral stereochemistry, except Co(4-ADI)2X2 (X = Cl, Br, I, SCN, ClO4).
Abstract: Complexes of the type M(4-ADI)nX2 · mH2O (where 4-ADI = 4-amino-3,5-dimethylisoxazole; n = 1–4; X = Cl, Br, I, SCN, ClO4; m = 1–4) have been studied by i.r. and electronic spectroscopy, magnetic and conductivity measurements. The ligand behaves as a monodentate -NH2 bonded species in monomeric complexes, but as a bridging ligand-NH2 and -N(ring) bonded species in polymeric complexes. All the compounds have an octahedral stereochemistry, except Co(4-ADI)2X2 (X = Cl, Br, I) complexes, which are tetrahedral.
01 Jan 1978
TL;DR: In this paper, the results of leucite leaching with thiobacilli, even in the presence of pyrite, and with some strains of soil microorganisms did not give good results.
Abstract: Leuoite is a framework silicate (2SiO 2 ·AlO 2 ) -1 ·K +1 with a specific gravity of 2.5, Mohs hardness about 6, and vitreous luster. It is tetragonal (pseudocubic) and can be differentiated from orthoclase because of its lower silica content (four molecules in leucite vs. six in orthoclase). It is more basic and more susceptible to acid attack and weathering than orthoclase. In the volcanic belt of Central Italy, comprised between Upper Latium and the Alban Hills and in nearby areas, there exist large occurrences of leucitic rocks containing estimated reserves of nine billion tons of potassium oxide (K 2 O) equivalent and the same amount of aluminum oxide (Al 2 O 3 ). Numerous attempts aimed at developing industrial processes of potassium extraction from leucite ores date as far back as 1856, but so far they have not been successful. Microbial solubilization of potassium and aluminum from leucite using heterotrophic microorganisms from collections or isolated from soils of leucitic areas and thiobacilli was studied in static conditions (batch cultures). Leaching with thiobacilli, even in the presence of pyrite, and with some strains of soil microorganisms did not give good results. In 150 days, strains of Aspergillus niger (van Tieghen) , Scopulariopsis brevicaule (Sacc. Bain) and Penicillium expansum (Link) leached between 21 and 27% of the potassium.
TL;DR: The results indicate the existence of two DA-receptor-mediated mechanisms regulating DA-synthesis in vivo: one depending on the presence of post-synapticDA-receptors and capable of producing a stable activation of tyrosine-hydroxylase whereas the other is not associated to a persistent conformational change of tyrolysis.