Search PubMed⌕ Search

Biomedical subjects

G I Shul'gina

Publications and source records attributed to G I Shul'gina.

At least 19 recordsLinked to original sources
PubMed2005

[Effect of the GABA derivative phenibut on learning].

The learning effect of phenibut, a beta-phenyl derivative of the inhibitory neuromediator GABA, used in a subcutaneous dose of 40 mg/kg 2 hours before each experiment, was studied in rabbits. The injection of phenibut was shown to enhance not only the inhibitory, but also excitatory components of cerebral cortical neuronal responses to all applied stimuli. The findings support the concept that the GABAergic neuromediator system is involved in the elaboration of internal inhibition and explain the sense of intracerebral processes that ensure both the sedative properties of phenibut and its ability to improve patients' systemic tone and health status when brain dysfunctions are treated.

Animals↗
PubMed2000

[Effects of sodium nitrite, a NO donor, on activity of neurons in visual and sensorimotor regions of cortex during learning].

Administration of sodium nitrite, NO-generating agent, in a dose of 11 mg/kg to conscious rabbits eliminates the increased rates of movements to pain reinforcement which occurs as combinations of light flashes with electric cutaneous irritation recur in the control. Along with this, there is a reduction in the intensity and duration of short latent "modally specific" components in the neuronal responses of visual (to light flashes) and sensomotor (to pain reinforcement) regions of a new cortex. There were less changes in the late latent activation components of neuronal responses of the sensomotor and visual cortex to pain reinforcement, an inhibitory pause in visual neuronal responses to light flashes, its uninhibitory action of pain reinforcement after sodium nitrite administration. The findings suggest that sodium nitrite exerts a neurotropic effect on its systemic administration and support the views that there are differences in the neuromediatory provision of transmission of "modally specific" and "modally nonspecific" effects to the neurons of the new cortex on radiation.

Animals↗
PubMedDate not supplied

Neurobiology of the integrative activity of the brain. Dynamics of the activational and inhibitory types of synchronization of cortical neurons during the realization of a defensive reflex and of internal inhibition.

An increase in synchronization of the activational type (coincidence of the presence of impulse activity), and a decrease of the inhibitory type (coincidence of both the presence and absence of impulse activity), in the operation of close-lying neurons were observed in the visual and sensorimotor areas of the new cortex and in the hippocampus of wakeful non-immobilized rabbits in response to the combination of flashes of light with electrodermal stimulation (EDS) of the extremity. An increase in the synchronization of the neurons of the inhibitory type took place in the visual cortex in response to flashes against the background of the conditional inhibitor, i.e., continuous light, and changes in synchronization, similar to the effect of pain reinforcement but significantly weaker, appeared in the sensorimotor cortex and in the hippocampus. An increase in synchronicity of the activational type took place primarily in pairs of neurons with increase in the same direction in the frequency of impulse activity in response to a stimulus, and of the inhibitory type, took place with its decrease. In addition, both kinds of changes in synchronization appeared in a significant portion of the pairs of neurons with changes in the frequency of impulse activity of different directions.

Animals↗
PubMedDate not supplied

Dynamics of synchronization in the functioning of neurons of the new cortex and hippocampus during learning before and after the administration of nootropic agents and narcotics.

The principal difference in the effect of the preparations investigated resided in the fact that the nootropic agents did not change the effect of painful reinforcement on the synchronicity of neurons of the cerebral cortex of rabbits of the inhibitory type (coincidence of both the presence and absence of impulse activity), and of the activational type (the time of coincidence of only the presence of impulse activity). Both preparations mainly attenuated the initial influences of both the inhibitory and reinforced conditional stimuli on the synchronicity in the activity of the cortical neurons of both the activational and the inhibitory types.

Animals↗
PubMedDate not supplied

The influence of an enkephalin derivative, DAGO, on the behavior and activity of neurons of the neocortex and hippocampus of rabbits during the development of defensive and inhibitory conditioned reflexes.

After the administration of a morphine-like opiate, DAGO (D), in a dose of 250 micrograms/kg, a decrease was observed in the probability of movements of a rabbit in response to light flashes, the signal for a defensive reflex. The level of the background impulse activity of the neurons gradually decreased in the sensorimotor cortex and in the hippocampus, and did not change in the visual cortex. The decrease and the recovery of the responses of the neurons to the reinforcing stimulus (electrodermal stimulation of the limb) proceeded unidirectionally in all of the areas of the cortex studied, while there were substantial differences in the relationship to the cortical area studied and to the biological significance of the stimulus in the dynamics of the responses to the inhibitory and reinforced light flashes. The identification of the features of the systemic organization of the neurons during training with change in the properties of the reinforcement under the influence of the preparation under study is discussed, as well as the similarity of some features in the mechanisms of the development of internal inhibition in the defensive situation and of the properties of positive reinforcement.

Action Potentials↗
PubMedDate not supplied

Influence of dilantin on the reactions of neurons of the visual cortex and the behavior of rabbits during learning.

Changes in behavior in response to light flashes, the conditional stimulus of a defense reflex, were not observed following the administration of dilantin, a preparation which attenuates posttetanic potentiation, in rabbits with preliminarily developed defense and inhibitory conditioned reflexes; weak disinhibition of movements appeared in response to the action of flashes against the background of a conditional inhibitor. The similarity of the reactions of the neurons of the visual cortex to light flashes, the CS, with the responses to their joint action with the reinforcement, did not weaken in the majority of instances, while in several neurons, it intensified. The differences in the responses to reinforced and inhibitory light flashes did not disappear following the administration of dilantin, but they attenuated in some of the neurons due to filling of the inhibitory pause with impulses. The results obtained make it possible to draw the conclusion that posttetanic potentiation does not participate in the maintenance of developed conditioned reflexes.

Animals↗