Farmakologiia i toksikologiia最新文献

In the experiments on cats by the method of conditioned defensive reflexes there was studied the effect of a psychostimulant sydnocarb on differentiation of short-term and long-term visual stimuli, latencies of the responses to differentiated and single visual stimuli, the number of interstimulus responses, the time of taking a decision. The serotoninergic, dopaminergic and adrenergic substances were used to analyse the influences on the mediator systems. Syndocarb action was found to be mediated by the noradrenergic and serotoninergic systems.

The results of the experimental selection of the agents modifiers of the biological reactions derived from plants of the Siberia and Far East were generalized. On the models of transplanted tumours of mice and rats there was shown the possibility of increasing the antitumour resistance of the organism during the use of the plant-derived agents under conditions of chemotherapeutic and surgical treatment.

In the immobilized rats bemithyl (50 mg/kg in a single dose) was shown to normalize the state of the musculomotor and cardiovascular systems exerting the positive influence on the key links of the process of autoregulation in the form of the sedative (the central nervous system), stress-protective (hormonal regulation) and antihypoxic (metabolism) effects that characterizes it as the drug with the distinct antistress activity.

The antinociceptive effect of electrical nerve stimulation with low (2-4 V, 100 Hz, 5 min) and high (45 V, 1 Hz, 1 min) intensity in the unanesthetized rats with the transsected spinal cord was determined by microelectrode recording in the ventrolateral tracts. The action of low intensity stimulation was reduced by yohimbine or during antinociceptive effect of clonidine. It was potentiated by baclofen and physostigmine. Prazosin, bicuculline, methysergid, strychnin, atropine, muscimole, THIP did not influence the effect of low-intensity stimulation. Metysergide partially reduced the effect of high-intensity stimulation. The data suggest that 2-adrenoreceptors are involved in the action of low-intensity stimulation and 5-HT-receptors are involved in the action of high-intensity one. For potentiating the effect of low-intensity stimulation on the segmental level it is possible to use baclofen and physostigmine.

The preliminary inhibition of prostanoid biosynthesis by indomethacin (10 mg/kg, intravenously) strongly changes the typical anaphylactic shock reaction produced by the intracoronary injection of the challenging dose of the antigen in the dogs sensitized with normal horse serum. A rapid fall of blood pressure and cardiac output at the first stage of the anaphylactic reaction is sharply diminished, the reaction of the coronary vessels is inversed. Instead of dilatation, vasoconstriction occurred increasing with the repeated administration of the antigen. The data obtained suggest that the initial hypotension under anaphylactic shock is due to prostanoid production while the coronary spasm is the result of lipoxygenase activation.

The results of the isolated and combined effects of teturam and acetaldehyde indicate that a decrease of noradrenaline levels in the brain and heart is induced by teturam. An increase of adrenaline content in the hypothalamus is determined by acetaldehyde. In the adrenals the agents produce the oppositely directed changes in catecholamine content. Against the background of chronic administration of acetaldehyde teturam potentiates its influence on changes in noradrenaline levels in all tissues except the adrenals and adrenaline levels in the hypothalamus and brain stem.

The experiments on Wistar rats and chinchilla rabbits showed that EDIHYP (5 mg/kg intravenously) completely prevented cardiac fibrillation and mortality in rats with calcium-chloride-induced arrhythmias, (CaCl2-200 mg/kg intravenously). Administration of atropine (0.1 mg/kg, if administered subcutaneously, 30 minutes before the acute experiment) exerts no influence on the drug's antiarrhythmic activity but eliminates its cholinergic component--salivation and lacrimation. When administered in the same dose EDIHYP to a great extent prevents oubaine (strophanthin)-induced arrhythmias in rabbits but fails to influence aconitine-induced arrhythmias. This suggests that EDIHYP's ability of direct or indirect blockade of slow Ca-channels underlies the mechanism of its antiarrhythmic action.