Showing papers in "Patologicheskaia fiziologiia i èksperimental'naia terapiia in 1992"

Diffuse noxious inhibitory controls (DNIC) in animals and in man.

Abstract: Some neurones in the dorsal horn of the spinal cord are strongly inhibited when a nociceptive stimulus is applied to any part of the body, distinct from their excitatory receptive fields. This phenomenon was termed "Diffuse Noxious Inhibitory Controls" (DNIC). DNIC influence only convergent neurones: the other cell types which are found in the dorsal horn, including specific nociceptive neurones, are not affected by this type of control. In normal conditions, these inhibitions can be triggered only by conditioning stimuli which are nociceptive. The inhibitions are then extremely potent, affect all the activities of the convergent neurones and persist, sometimes for several minutes, after the removal of the conditioning stimulus. In fact, only activity of A delta- or A delta- and C-peripheral fibres can trigger DNIC. DNIC are sustained by a complex loop which involves supraspinal structures since, unlike segmental inhibitions, they can not be observed in animals in which the cord has previously been transsected at the cervical level. The ascending and descending limbs of this loop travel respectively through the ventro-lateral and dorso-lateral funiculi respectively. We proposed that DNIC result from the physiological activation of some brain structures putatively involved in descending inhibition. However, lesions of the following structures did not modify DNIC: Periaqueductal grey (PAG), Cuneiform nucleus, Parabrachial area, locus coeruleus/subcoeruleus, rostral ventromedial medulla (RVM) including Raphe Magnus, Gigantocellularis and Paragigantocellularis nuclei. By contrast, lesions of Subnucleus Reticularis Dorsalis (SPD) in the caudal medulla strongly reduced DNIC. Both electrophysiological and anatomical data support the involvement of SRD neurones in spin-bulbo-spinal loop(s). Indeed, they are unresponsive to visual, auditory or proprioceptive stimulation but are preferentially or exclusively activated by nociceptive stimuli with a "whole-body receptive field"; they encode precisely the intensity of cutaneous and visceral stimulation within the noxious range and are exclusively activated by cutaneous A delta- or A delta- and C-fibre peripheral volleys; they send descending projections through the dorsolateral funiculus that terminate in the dorsal horn at all levels of the spinal cord. In man, exactly analogous results have been obtained by means of combined psychophysical measurements and recordings of nociceptive reflexes. Electrical stimulation of the sural nerve at the ankle simultaneously induces a nociceptive reflex in a flexor muscle of the knee (the RIII reflex) and a painful sensation from the territory of the nerve. Painful heterotopic conditioning stimuli, no matter whether thermal, mechanical or chemical in nature, depress both the reflex and the associated painful sensation, with stronger effects being observed with more intense conditioning stimuli.(ABSTRACT TRUNCATED AT 400 WORDS)

Phantom limb pain.

Abstract: A phantom limb is universally experienced after a limb has been amputated or its sensory roots have been destroyed. A complete break of the spinal cord also often leads to a phantom body below the level of the break. Furthermore, phantom breasts, genitals and other body areas occur in a substantial number of people after surgical removal or denervation of the body part. The most astonishing feature of a phantom limb (or other body area) is its incredible "reality" to the person. An examination of phantom limb phenomena has led to a new theory. It is proposed that we are born with a widespread neural network--the "neuromatrix"--for the body-self, which is subsequently modified by experience. The neuromatrix imparts a pattern--the "neurosignature"--on all inputs from the body, so that experiences of one's own body have a quality of self and are imbued with affective tone and cognitive meaning. The theory is presented with supporting evidence as well as implications for research.

Laser irradiation of venous blood for prevention of reperfusion syndrome in myocardial infarction

Abstract: The antioxidant effect encountered in laser irradiation of venous blood suggested the study of the possibility of its use for the prevention of the reperfusion syndrome in myocardial infarction (MI). Analysis of biochemical, electrophysiological, hemodynamic, and morphohistological data obtained in experiments on male rats and in clinical cases showed that irradiation of venous blood by the LG-75 helium-neon laser with a wavelength of 632.8 nm produced the best effect. The effect is realized through increase of collateral blood supply in the region of the MI and the antioxidant and antihypoxic action.

[Effect of extremely high-frequency electromagnetic radiation on the function of skin sensory endings].

Abstract: The specific features of skin receptor function on the sole of the hind limb of an albino rat were studied in an acute experiment. Impulse activity recorded from the solitary fibres of the tibial nerve showed that receptor units (RU) responded to mechanical stimulation of the skin. Irradiation of the skin surface by low-intensity millimeter band electromagnetic field (frequencies of 55.61 and 73 GHz) in the zone of the RU led to diminution of RU sensitivity to the mechanical stimulus. One half of the RU ceased to respond to the mechanical stimulation 25 minutes after irradiation. The other half continued responding to stimulation even after 35 minutes of irradiation, but the character of the RU response was significantly changed. A strict frequency-resonance dependence of the biological effects was revealed. It is concluded that electromagnetic radiation has a modulatory-inhibiting effect on the skin RU. The authors suggest a possible mechanism of realization of the effect of electromagnetic radiation of extremely high-frequencies and low power on the skin receptor function.

Sequelae of biochemical events following photochemical injury of rat sensory-motor cortex: mechanism of ganglioside protection.

Abstract: In culture the protracted and abusive stimulation of glutamate (GLU) receptors results in neuronal death through a mechanism involving the persistent translocation of PKC and the destabilization of (Ca2+)i homeostasis [(Ca2+)i HD]. In contrast, intermittent GLU receptor use elicits a coordinated expression of immediate early genes (IEG) acting as nuclear third messenger. Brain ischemia also is known to result in the paroxysmal abusive stimulation of glutamate receptors. The glutamate receptive elements in turn degenerate largely as a function of their inability to control homeostatic Ca2+ due to the irreversible translocation of PKC. In the present study we employed an in vivo model of focal brain ischemia using the photosensitive dye, Rose bengal. With this model we sought to determine the neuroprotective actions of MK-801, a noncompetitive blocker of GLU at the NMDA-sensitive receptor and of the semisynthetic gangliosides LIGA 4 and LIGA 20 which in vitro have been demonstrated to block PKC translocation. Moreover, we sought to establish whether the persistent stimulation of ionotropic glutamate receptors would led to a change in ionotropic glutamate expression in the focal and perifocal area. Importantly, the perifocal area (i. e., the region surrounding the area of primary insult) is a region in which profound cellular reorganization occurs including neuronal death and glial proliferation and is a key region to target various neuroprotective drugs aimed at ameliorating the neurodegeneration following stroke. Receptor abuse dependent antagonists (RADA) drugs such as gangliosides selectively curtail the amplification steps that specifically differentiate signal transduction following physiological receptor use from that following pathological receptor abuse.(ABSTRACT TRUNCATED AT 250 WORDS)

Antiamnesic properties of some neuropeptides and the involvement of neurotransmitters in the rats.

Abstract: The effects of certain neuropeptides on electroconvulsive (ECS) shock-induced amnesia were studied in rats. The ECS was applied immediately after the learning a one-trial passive avoidance paradigm. The peptides--rat atrial natriuretic peptide (rANP 1-28, ANP), porcine brain natriuretic peptide (pBNP 1-32, BNP), rat calcitonin gene-related peptide (CGRP) and bombesin--were injected into the lateral brain ventricle 30 min after the ECS. In order to study the possible role of neurotransmitters in mediating the action of the peptides on amnesia, the animals were treated immediately after the ECS with, doses which themselves did not modify either the learning itself or the amnesic action of the ECS. All the above peptides attenuated the ECS-induced amnesia, but the transmitters involved in these actions differed. The anticonvulsive action of ANP was prevented by haloperidol (10 micrograms/kg i. p.), propranolol (10 mg/kg i. p.) and atropine (2 mg/kg i. p.). Phenoxybenzamine (2.0 mg/kg i. p.), bicuculline (1 mg/kg i. p.), methysergide (5 mg/kg i. p.) and naloxone (0.3 mg/kg i. p.) had no effect. Besides alpha-adrenergic and cholinergic receptor blockers the beta-adrenergic blocker propranolol was also effective in preventing the antiamnesic action of the BNP. As concerns the action of bombesin, only haloperidol was effective. Alpha- and beta-adrenergic and cholinergic receptor blockers and opiates are involved in the antiamnesic properties of CGRP. The results showed that, despite the fact that the studied, peptides attenuated the ECS-induced amnesia, different transmitters are involved in their action.

Content of trace elements and steroid hormones in blood and tissues of internal organs of rats during an inflammatory process in the bronchi

Abstract: Prolonged interrupted inhalation of nitrogen dioxide in a dose of 36.0 +/- 2.2 mg/m3 was attended by definite morphological signs of inflammation in the lungs of rats (hyperplasia of goblet cells, thickening of the basilar membrane, differentiation of ciliated epithelium, etc.), reduction of the zinc content in all studied tissues and testosterone levels in blood. Intramuscular injection of 1% testosterone propionate normalized the blood level of the hormone and influenced the synthetic processes in the cells of the bronchial epithelium and the rate of its regeneration. To raise the efficacy of the correction of the pathological process in the lungs it is suggested that hormonal therapy should be combined with correction of zinc deficiency in the organism.

Second messengers derived from excitable membranes are involved in ischemic and seizure-related brain damage.

Abstract: The intracellular accumulation of PAF following cell stimulation suggests an intracellular signal transduction pathway. High affinity binding sites for PAF in microsomal membranes and displacement of PAF from these sites by structurally distinct PAF antagonists suggests the existence of an intracellular receptor. Suppression of primary genomic responses by a PAF antagonist selective for the intracellular Ca2+ and arachidonic acid metabolites, is linking the intracellular generation of PAF to immediate-early transcription. Several of the metabolites that transiently accumulate after injury may elicit beneficial effects on regenerative processes. The membrane metabolite PAF, which accumulates after seizure and ischemia, may initiate reparative processes by promoting transcriptional activation of immediate-early transcription factors. The long-term effects of these immediate-early gene transcription factors may provide a synthetic mechanism to replenish and rebuild cells following traumatic events.

Immediate-early genes in the nervous system-are they involved in mechanisms of chronic pain?

Abstract: Evidence suggests that long-term changes in the nervous system may represent a cause of chronic pain. Recent processes became accessible at the cellular level of the nervous system by analyzing immediate-early genes (IEG). The nuclear proteins encoded by these genes function as transcription factors, i.e. they control the expression of other genes. Many conditions of physiological and pathological stimulation can activate IEGs in the nervous system, and these findings have led to the concept of "stimulation-transcription-coupling". Noxious stimuli such as electrical C-fibre stimulation, noxious skin heating or subcutaneous formalin injection result in the transsynaptic induction of the IEG encoded proteins c-Fos, C-Jun and Krox-24, in the dorsal horn of the spinal cord. Non-noxious stimuli usually fail to induce the expression of IEGs. Nerve lesions result in a selective expression of C-Jun protein in the axotomized nerve cells, both in the peripheral and central nervous systems. Expression of IEGs after noxious stimuli and nerve lesions last for days or weeks, indicating profound alterations in the biochemistry and function of nerve cells. These changes could be involved in central nervous mechanisms of chronic pain.

Pathophysiological significance of brain acidic fibroblast growth factor.

Abstract: The acidic fibroblast growth factor (aFGF) in rat cerebrospinal fluid (CSF) increased 1000 times in the 2 hr period after food intake, or intraperitoneal (IP) or intracerebroventricular (ICV) glucose infusion. It diffused into the brain parenchyma and was taken up into neurons in the hypothalamus, hippocampus, etc.... aFGF is produced in the ependymal cells and released into CSF in response to increased glucose. ICV application of aFGF dose dependently inhibits, and anti-aFGF antibody facilitates food intake. IP injection of glucose 2 hr before a task that combined acquisition with passive avoidance significantly increased retention of avoidance by mice tested 24 hr later. In a Morris water maze task, IP glucose injection 2 hr before a first trial block reduced time to find and climb onto a platform hidden just below the water surface. These facilitation by glucose of affective and spatial memory were abolished by pretreatment with anti-aFGF antibody applied ICV. Continuous ICV infusion of aFGF into rats also significantly increased the reliability of passive avoidance for several days. The memory facilitation by aFGF was significantly attenuated by CA1 neuron death in the hippocampus caused by 5 min ischemia of the brain, in gerbils. After food intake, centrally-released aFGF reaches the hippocampus and facilitates memory, while peripherally released cholecystokinin reaches the endings of the afferent vagal nerves in the portal vein and changes the vagal nerve activity, which modulates hippocampal activity, to lead to memory facilitation. This, however, is blocked by vagotomy below the diaphragm.(ABSTRACT TRUNCATED AT 250 WORDS)

[Immunotropic activity of human alpha1-glucoprotein].

Abstract: Experiments were conducted to study the effect of alpha-acid glycoprotein on a fatal infection caused by Pseudomonas pyocyanea, growth of melanoma B-16, and transplantation of a skin graft from C57BL/6 mice to CBA mice. Injection of the agent significantly increased the anti-infection resistance in mice, suppressed growth of melanoma-16, and prolonged the survival of the skin grafts, which was evidence of marked glycoprotein immunomodulating activity.

Nociceptive sensitivity of rabbits in varying localization of pain stimuli and naloxone administration

Abstract: Study of the dynamics of changes of evoked potential (EP) amplitude in electrodental and electrocutaneous stimulation (EDS and ECS, respectively) as an index of the perceptual component of the nociceptive reaction showed that 0.2 mg/kg and 0.5 mg/kg doses of naloxone produce both a hyper- and an analgesic effect in rabbits. The effect of naloxone depended on the individual properties of the rabbits, while its degree was determined by the localization of the nociceptive stimulus. The animals' individual properties were manifested by the presence or absence of an analgesic effect of auricular electrostimulation--acupuncture-sensitive (AS) or acupuncture-resistant (AR) rabbits. Naloxone injection caused a dose-dependent hyperalgesic effect in AS animals and an analgesic effect in AR rabbits in EDS. Similar effects were recorded in ECS, but their degree differed: hyperalgesia in AS rabbits was demonstrated more clearly than analgesia in AR animals.

Zinc content in pancreatic islets in experimental diabetes induced by chelating agents

Abstract: The zinc content in microresected islets of rabbits, mice, rats, and guinea pigs was determined by atom-absorption spectrophotometry. The content was found to be highest in rabbits, and diabetes was induced in them by chelating agents easily. Injection of dithizone or 8-(p-toluenesulfonylamine) quinoline failed to induce diabetes mellitus in mice, rats, and guinea pigs. It is concluded that diabetogenic chelating agents are capable of producing irreversible diabetogenic affection in those beta-cells which contain a critical concentration of reactant zinc.

[Stress: postulates, analysis in terms of the general theory of functional systems].

Abstract: Further developing of the general theory of stress, put forward by Selye, the theory of functional systems treats stress, of any origin, as a systemic response of the organism to a conflict situation. The theory of functional systems regards, along with the action of stressors, the conflict behavioral situation in which the subjects are deprived of a possibility to satisfy their main requirements, i. e. attainment of useful adaptation results, as the leading cause of stress. It is the conflict behavioral situation that gives rise to the primary reaction of the organism, viz. psychoemotional stress. Cerebral mechanisms of emotional stress in terms of the theory of functional systems are primary in the pathogenesis of psychomotor disorders in stress. The specific neurochemical changes in the limbico-reticular structures of the brain, certain neurochemical disintegration of the neuronal elements, constituting the limbico-reticular structures of the brain, underlie emotional stress. Our experiments showed that predisposition to emotional stress is accounted for by the decreased level of catecholamines and certain oligopeptides such as substance PI (?), beta-endorphins, peptide, causing delta-sleep in the limbico-reticular structures of the brain.(ABSTRACT TRUNCATED AT 250 WORDS)

Potential physiological and pathophysiological roles of nitric oxide in the brain.

Abstract: Nitric oxide (NO) is a free radical molecule which has been described to play a role as a messenger molecule in at least three systems: white blood cells, blood vessels and most recently in the nervous system. In the brain, NO is produced enzymatically in postsynaptic structures in response to activation of excitatory amino acid receptors. A major action of NO is to activate soluble guanylate cyclase and to raise cGMP level in target cells. The role of NO as a messenger in long-term potentiation and in long-term depression has been established and recent studies have directly implicated NO in neuronal damage associated with vascular strokes. Concerning the role of NO in the excitatory amino acid neurotoxicity, more studies will be necessary to elucidate the implication of NO mediating neuronal damage. Whatever the exact function of NO, it is sure that this substance play an important role in the brain and that pharmacological manipulations of NO pathway will constitute a novel approach for therapeutical applications in the future.

Effect of staphylococcal toxin on the microcirculatory system

Abstract: Study of microcirculation in the mesentery of narcotized rats showed that the staphylococcal toxin causes increased migration of leukocytes, aggregation of formed elements, and disturbance of the blood flow in the small venules and arterioles. The toxin stimulates rhythmic contractile activity of the lymphatic microvessels and induces their constriction and even complete obliteration. The lymphoconstrictive effect of the toxin is weakened by verapamil and completely removed by dimethyl sulfoxide.

[Comparative evaluation of the wound-healing effect of benzofuracaine, etaden, and xanthinol nicotinate in an experiment].

Abstract: The effect of benzofuracaine, etaden, and xanthinol nicotinate on the healing of skin wounds was studied in rat experiments. On days 1-14 of postmechanical injury, intramuscular benzofuracaine (15, 30, 60, and 120 mg/kg), etaden (20 mg/kg), and xanthinol nicotinate (each drug alone) reparative processes in the skin wounds developed more rapidly and processes of microcirculation in the region of the injury were normalized. The wound-healing effect of benzofurocaine in an ortimal dose of 60 mg/kg was more marked than that op etaden and xanthinol nicotinate. With benzofuracaine and etaden, the skin wounds healed completely by the 14th day of the experiment in 57% and 28.6% of animals, respectively. Such cases were not encountered among animals treated with xanthinol nicotinate and in the controls (untreated animals).

Biological effect of laser radiation on the functional state of cardiomyocytes

Abstract: Experiments were conducted on Wistar rats to study the effect of laser radiation (LR) with a wavelength of 632.8 and 890.0 nm and power of 0.0005-0.005 and 0.003-0.003 W/cm2, respectively, on the action potential (AP) and mechanical contraction of smooth muscle cells, as well as myocardial ATPase activity. LR with a wavelength of 632.8 and 890.0 nm in a dose of 3.0 J/cm2 activates Ca-ATP-ase activity, increases the activity of the myocardial antioxidant system, reduces the Na-Ca current through the membrane, and accelerates the return of Ca2+ into the sarcoplasmic reticulum. LR with a wavelength of 632.8 nm reduces mainly the Ca flow, while LR with a wavelength of 890.0 nm reduces the Na current In a dose of more than 3.0 J/cm2 LR causes a damaging effect manifested by increased Ca2+ current in the slow channels, increase of amplitude, duration of AP and repolarization phase. Synergism of the action of LR with a wavelength of 632.8 and 890.0 nm and that of some antiarrhythmic agents (procainamide, lidocaine, ethmosin, ethacisin, verapamil) was encountered.

Use of superoxide dismutase in infusion therapy of experimental hemorrhagic shock

Abstract: The work deals with study of the possibility of increasing the efficacy of infusion therapy in massive blood loss by preliminary administration of superoxide dismutase (SOD). The data obtained bear evidence that in preliminary administration of SOD infusion of a blood substitute produces a more marked and stable improvement of central hemodynamics and microcirculation, oxygen regimen, and acid-base equilibrium in rats. A significant increase of the circulation volume and stroke volume of the heart following SOD injection may be linked with lesser intensity of lipid peroxidation in the cardiocyte membranes during reoxygenation.

[Kinetics of myoglobin, creatine kinase and aspartate aminotransferase in uncomplicated and complicated forms of healing of experimental myocardial infarction].

Abstract: It was demonstrated in experiments on 60 dogs that in hyporeactive myocardial infarction (MI) myoglobin (MG) concentration and the activity of creatine kinase (CK) and aspartate aminotransferase (ASAT) increase at a slower rate and reach maximum values later. In hyperreactive MI the rate of their increase and the time of attainment of maximum values are, respectively, greater and earlier than in normoreactive MI. The connection of MG, CK, and ASAT changes with reactivity allows them to be used in prognosticating MI healing.

Effect of the antioxidant ionol on myocardial energy metabolism and the course of traumatic shock

Abstract: Energy metabolism was studied in experiments on rats with due regard for the individual features of the organism's reaction to trauma. The animals were divided into 2 subgroups according to the survival period during the experiment. Disorders of mitochondrial function were revealed in both subgroups, but they differed in degree according to the severity of the process. Preliminary injection of the antioxidant ionol prolonged the animals' survival and prevented disorders of mitochondrial function. The article discusses the possibility of preventing activation of free-radical oxidation of the membrane lipids and removal of their damaging effect on the mitochondria with ionol.

Insulin sensitivity during use of adrenoblockers and adrenomimetics

Abstract: The effect of adrenergic blocking agents and adrenomimetics on sensitivity to insulin was studied in rat experiments. The sensitivity was judged from the duration of hypoglycemic coma development after intravenous infusion of 40 U/kg insulin. Sensitivity to insulin increased with the beta-adrenergic blocking agent obsidan and the alpha-adrenomimetic mesaton (phenylephrine hydrochloride) but diminished after infusion of the beta-adrenomimetic partusisten and the alpha-adrenergic blocking agent butyroxane. The obtained data are discussed from the standpoint of insulin-resistance control.

Change in various properties of catalase in the small intestine of rats after vagotomy

Abstract: To evaluate the antioxidative system of the small intestine in disturbed parasympathetic innervation, the authors studied the activity of catalase, its resistance to substrate inactivation (catalytic capacity) and reduction potential (reduction of Fe3+ to Fe2+) in the enteric homogenate in different periods (on day 14 and 30) after bilateral subdiaphragmatic truncal vagotomy. Vagotomy did not change catalase activity but was attended by an increase of catalase catalytic capacity and reduction potential. It is suggested that the discovered changes of the studied parameters are manifestations of responses of the antioxidative protective system of the small intestine to the activation of lipid peroxidation.

Ultrastructure of erythrocytes with diminished flow properties and their role in the development of microcirculatory disorders under extreme conditions

Abstract: The deformability (D) of erythrocytes and their ultrastructure in the microcirculatory channel of vital tissues of the organism were studied in experiments on rabbits in two types of extreme conditions: staphylococci toxicosis and the postischemic syndrome. Erythrocyte deformability in each of these extreme conditions occurred in the late phase of the process and was manifested by destruction of the ultrastructural organization of the membrane matrix and the cytoplasm of cells in the microvessels. Destruction of the erythrocyte membranes was linked with their disintegration into micro- and macro-fragments (in staphylococci toxicosis) and separation of membrane areas in the form of microvesicles (in the postischemic syndrome). Damage to the erythrocyte membrane and cytoplasm may be considered to be one of the typical manifestations of the organism's response to extreme effects accompanying the phenomena of disseminated intravascular clotting.

Role of the opioid system in prevention of ischemic disorders of cardiac rhythm during adaptation to cold and physical exertion in rats

Abstract: It was found that adaptation of rats to cold and physical exercise prevented ventricular fibrillation caused by occlusion of the left anterior coronary artery. Adaptation to cold or only to physical exercise did not prevent ventricular arrhythmias. A significant increase of the beta-endorphin content in the hypophysis and hypothalamus was demonstrated in all adapted rats. An increased content of meth-enkephalin (ME) in the myocardium was found only in rats adapted to cold and physical exercise. It is suggested that increase of the myocardial ME content is of essential significance in the antiarrhythmic action of adaptation.

Content of trace elements and steroid hormones in blood and tissues of internal organs in experimental pulmonary fibrosis induced by intratracheal administration of bleomycetin

Abstract: Pulmonary fibrosis was produced in rats by intratracheal administration of bleomycetin. The development of the fibrous process in the lungs was attended by marked reduction of the zinc content in the tissues of the viscera, plasma, and formed elements of the blood, as well as of corticosterone and testosterone in blood plasma. Respiratory insufficiency is a probable cause of the developing zinc-deficiency which leads to disturbed synthesis of steroid hormones. Injection of exogenous testosterone normalizes partly the level of steroid hormones in the blood, improves the general condition of the animals, and facilitates an increase of body weight.

[Effect of cultured Polyscias cells on the activity of components of the protein-synthesizing system of rabbit liver].

Abstract: The authors studied teh effect of cultured Polyscias filcifolia Bailey cells on protein biosynthesis in an acellular system obtained from the liver of rabbits in experimental myocardial ischemia. It was found that the preparation normalizes the values of protein biosynthesis, the duration of the average polypeptide chain synthesis, and the activity of aminoacyl-tRNA synthetases.