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Biomedical subjects

A I Machula

Publications and source records attributed to A I Machula.

At least 19 recordsLinked to original sources
PubMed1990

[Participation of dihydropyridine-sensitive calcium channels in psychotropic effects of nootropic drugs].

Administration of Ca-entry blockers with different chemical structure before the braining sessions produced the reduction of memory retention in mice and rats in the one-trial passive avoidance tests. This effect was absent in animals treated immediately after training test. Nootropic drugs piracetam and oxiracetam corrected the retention of memory when injected just after training test. Chronic treatment of rats with increasing doses of the nootropic drugs produced about two-fold tissue-specific elevation in the density of DHP-receptors, associated with L-type Ca-channels in synaptosomal membranes of rat cerebral cortex. Maximal effect was observed in a dose of 10 mg/kg. Diltiazem, administrated in a dose of 10 mg/kg, produced about two-fold decrease in the receptors density measured 24 hrs after the first injection. Oxiracetam (10 mg/kg) completely antagonized the effect of Ca-entry blocker. These data imply that nootropic action of piracetam and oxiracetam is mediated by L-type Ca-channels.

Animals↗
PubMed1987

[Structural analysis of the functional status of the brain as affected by bemethyl using pattern recognition theory].

Evoked visual potentials in associated, parietal and second somatosensory zones of the neocortex were analysed in trained cats using implanted electrodes. The influence of bemethyl on the structure of behavioral reactions was analysed using theoretical methods of perceptual images, particularly the method of cluster analysis. Bemethyl was shown to increase the level of interaction between the functional elements of the system, leading to a more stable resolution of problems facing the system, as compared to the initial state.

Animals↗
PubMed1985

A study of the mediator spectrum of delta-9 tetrahydrocanabinol effects on cerebral bioelectric activity.

Defense conditioning in cats with simultaneous recording of bioelectric activity was used to show that serotonin-negative and dopamine-positive substances normalize delta-9 THC-elicited dissimilarity of amplitudinal and temporal parameters of evoked potentials in visual associative and somatosensoric zones II of the cerebral cortex. It was also found that serotoninergic substances affect both primary and secondary waves of evoked potentials while dopaminergic substances influence only late waves.

Animals↗
PubMed1983

Mediator mechanisms of cathinone effects on animal behaviour.

The effect of cathinone on the visual differentiation of cats was investigated by the method of defense conditioned reflexes. It was found that cathinone decreases the differentiation of both the short-term and prolonged visual stimuli. These effects of cathinone increase when the serotoninergic system is activated and decrease under dopaminergic system activation.

Alkaloids↗
PubMedDate not supplied

[The role of the monoaminergic component in realizing the effect of sydnocarb on the differentiation of visual stimuli].

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.

Animals↗
PubMedDate not supplied

[Feasibility of applying pattern recognition techniques in psychopharmacology].

The necessity to consider the effect of psychotropic agents on the human organism as on the integral system interrelated with the environment is grounded. The need of applying the pattern recognition theory techniques which allow to analyze the integral state of the organism is substantiated. An illustration of the analysis of a psychotropic agent cathinone by using these techniques is presented.

Alkaloids↗
PubMedDate not supplied

[Spatial-temporal structure of the organization of goal-directed behavior under the action of delta 9-tetrahydrocannabinol].

The effect of delta-9-tetrahydrocannabinol (delta-9-THC) on the goal-directed behavior was studied by the pattern recognition theory methods on cats trained for a differentiated response, to structured visual stimuli. Administration of delta-9-THC was shown to cause noncoordination of certain neocortex regions as well as disagreement of temporal characteristics of the processes involved in the goal-directed behavior organization.

Animals↗
PubMedDate not supplied

[Aspects of the mediator nature of the effect of delta-9-tetrahydrocannabinol on evoked potentials of the cerebral cortex].

It has been shown on cats with the method of the conditional defensive reflexes and parallel recording of the bioelectric activity that the serotonin-negative and dopamine-positive substances restore the similarity of the amplitude-temporary parameters of evoked potentials in the visual, associative and the second comatosencory fields of the brain cortex, disturbed by delta-9-tetrahydrocannabinol injection. It has been also demonstrated that the serotoninergic substances influence the action of delta-9-tetrahydrocannabinol both on the early and late waves of evoked potentials whereas the dopaminergic substances influence the drug action only on the late waves.

Animals↗
PubMedDate not supplied

[Effect of tranquilizers on cerebral cortex excitability in cats].

Chronic tests on cats showed that diazepam and nitrazepam lower the amplitude of primary responses (PR) of the second somatosensory zone of the brain cortex both to a single and paired stimulation of the thalamo-cortical radiation of fibers. Meprotan, while potentiating the PR to a single stimulation, does not influence the course of the PR restitution cycles. Benacryzine, while enhancing the PR to a single stimulation, produces the appearance of a lengthy phase of depression throughout the PR restitution cycle. In acute tests with unanesthetized, flaxedil immobilized cats, with an isolated cortical band underneath a stimulating electrode, analogous changes in PR both to a single and paired stimulation of the thalamo-cortical radiation of fibers were noted.

Animals↗