PubMed Health⌕ Search

Biomedical subjects

A N Bakuradze

Publications and source records attributed to A N Bakuradze.

At least 19 recordsLinked to original sources
PubMed1986

[Effect of various cations on the secretory and acid-forming function of the stomach].

The data obtained suggest that the sodium ions (0.5-2.0 g) reduce the gastric juice secretion and its acidity whereas magnesium and calcium ions increase the latter. Potassium ions exert practically no effect on the acidity. The suppressing effect of the sodium ions seems to be connected with an increase excretion of sodium chloride with urine as well as with increased diuresis in general. Saluretics suppress the secretion and acidity of the gastric juice on account of increased diuresis and subsequent excretion of large amount of chlorides as well as by means of serotonin release from the Ec cells of the gastro-intestinal tract, the action of serotonin being actualized on the level of the gastric glands' cells, parietal those in particular.

Animals↗
PubMed1985

[Effect of nasal respiration on the electrical activity of skeletal musculature].

Spontaneous electrical activity of human gastrocnemius and deltoid muscles was studied after physical overloading under the conditions of nasal or oral respiration. In nasal respiration, the electrical activity was enhansed as compared with oral respiration: stimulation of the nasal cavity receptors with air current seems to improve the respiratory center work and to produce optimal conditions for a wider irradiation of excitatory impulses from the respiratory center to the nerve-skeletal apparatus regulating the motor activity of the body.

Adult↗
PubMed1985

[Role of emotional excitation in mechanisms of spatial short-term memory in lower monkeys].

Correlates of the changes of emotional tension level were studied in adult macaca rhesus. Simultaneous appearance of skin-galvanic responses and changes of heart rate were shown to reflect the increase of emotional tension level. The latter was revealed with continuous recording of the above vegetative indices during presentation of conditioned signals and performance of spatial delayed response. Emotiogenic structures are supposed to have a promoting effect on functioning of the mechanisms of spatial short-term memory during the period of spatial discrimination of conditioned signals and food-procuring instrumental behaviour.

Animals↗
PubMed1976

[The predominantly unilateral influence of the posterior hypothalamus on the neocortex].

High-frequency electrical stimulation of the-posterior hypothalamus applied 10-20 days after the sectioning of the brain stem at the level of the anterior frontal margins of the anterior coliculus results in the preferential activation of the ipsilateral neocortex. When unilateral lesions are placed in the posterior hypothalamus, the predominance of synchronous activity in the ipsilateral neocortex is observed. In the premesencephalic preparations, weak single electrical stimulation of the posterior hypothalamus provokes spindles in the ipsilateral portions of the frontal cortex. At more intensive single stimulation of the posterior hypothalamus there occurs diffuse appearance of spindles in different neocortical areas. Besides the preferential unilateral effect, the influence of the posterior hypothalamus is more prominent in the frontal than in the occipital regions of the cortex. It is suggested that the posterior hypothalamus exerts its influence on the neocortex through the thalamic nuclei.

Animals↗
PubMed1976

[The effect of stimulation of the posterior hypothalamus on the electrical activity of the neocortex in chronically premesencephalic cats].

Experiments were carried out on 19 adult cats with chronic brain stem transections at the level of the foremost border of the supperior colliculus. High-frequency electric stimulation of the posterior hypothalamus produced in these cats desynchronization of electrical activity in different parts of the neocortex. A predominant influence from the posterior hypothalamus on the electrical activity of frontal lobes was observed. On the basis of the obtained data, it is suggested that the influences from posterior hypothalamus elicit neocortical activation via thalamic nuclei.

Animals↗
PubMed1976

[The role of several brain stem structures in activation of the neocortex and motor reflexes in chronically premesencephalic cats].

Chronic experiments were carried out in 18 cats. After premesencephalic section of the brain-stem, the neocortex can be activated both spontaneously and in response to the posterior hypothalamus or the forepaw skin stimulation. After bilateral lesions in the posterior hypothalamus, neither spontaneous nor the forepaw-skin stimulation-produced activation of the neocortex, was observed. Excitation of the mesencephalic RF is accompanied by activation of motor reflexes. A conclusion was made that the posterior hypothalamus, independently of the mesencephalic RF, is capable of activating the neocortex, while the mesencephalic RF, independently of the rostral structures, is responsible for the motor reflex activation.

Animals↗
PubMed1975

[Participation of the posterior hypothalamus in the activity of the ascending activating system].

In chronic experiments on cats with premezencaphalic section of the brain stem electrica stimulation of the posterior hypothalamus caused desynchronization of the electrical activity of the neocortex. After the isolated injury of the posterior hypothalamus a moderate electrical stimulation of the medical part of the midbrain reticular formation failed to cause any pronounced activation of the neocortex. The results obtained indicated an important role of the posterior hypothalamus in the function of the ascending activating system.

Animals↗
PubMed1975

[The role of several limbic structures in neocortical activation following brain stem section at the level of the corpora quadrigemina].

In chronic experiments on 25 adult cats, after transection of the brain-stem at the level of oral margins of the anterior colliculus, the effect of high-frequency electrical stimulation of the posterior hypothalamus and basal-lateral portion of the amygdala was studied. While stimulation of the posterior hypothalamus resulted in diffuse activation, that of basal-lateral portion of the amygdala rather rarely evoked a relatively weak long-latency activation of the neocortex. Frequently, stimulation of the basal-lateral amygdala induced epileptiform activity in the neocortex. Bilateral lesion of the amygdaloid complex did not affect the activating influence of the posterior hypothalamus on neocortex. It is suggested that the posterior hypothalamus, independently of the mesencephalic reticular formation and amygdaloid complex, exerts an activating influence on the neocortex.

Amygdala↗
PubMed1975

[The effect of peripheral stimulation on the electrical activity of the neocortex in chronic premesencephalic cats].

Chronic experiments were carried out with 19 adult cats. It is demonstrated that following a premesencephalic sectioning of the brain stem, with the lemniscal pathways being spared, on the second and third day after the surgery, auditory, olfactory and skin stimulations caused diffusive activation of the neocortex. Photic stimulation, though evoking responses in the visual cortex, was unable to desynchronize the neocortical electrical activity. Taking into account the data on the organization of hypothalamic afferent connections, it is suggested that diffuse activation of the neocortex in cats, when the mesencephalic reticular formation is completely excluded, occurs during auditory, olfactory and skin stimulations due to excitation of the posterior hypothalamus.

Animals↗
PubMed1975

[Neocortical electrical activity of cats with premesencephalic brain stem section under chronic experimental conditions].

In 24 cats, premesencephalic section of the brain-stem affected the sleep-wakefulness cycle and caused desynchronization of the neocortical activity 3-4 days after total isolation of the mesencephalic RF. The data obtained corroborates the existence of a certain brain structure situated more rostrally than the mesencephalic RF which is able to cause by itself the neocortical activation.

Animals↗
PubMed1975

[Influence of the anterior and posterior hypothalamus on the conditioned reflex activity and delayed responses of lower simians].

In 4 adult monkeys, electrical stimulation of the anterior hypothalamus followed by subsidence in the animal and the ECoG synchronization evoked also an impairment of conditioned reflex activity and a decrease in the test performance during delayed responses. Strong stimulation of the posterior hypothalamus followed by emotional arousal and desynchronization in the ECoG, on the contrary, improved the conditioned reflex activity and increased the level of the test performance. The hypothalamus is then supposed to play a certain role in memory as an emotiogenic structure.

Animals↗
PubMedDate not supplied

Preferential ipsilateral influence of the posterior hypothalamus on the neocortex.

On the 10th--20th day after precollicular transection of the brain stem weak low-frequency electrical stimulation of the posterior hypothalamus preferentially activates the ipsilateral neocortex. After unilateral injury to the posterior hypothalamus, synchronous activity predominates in the ipsilateral neocortex. In premesencephalic animals weak single electrical stimulation of the posterior hypothalamus evokes the appearance of spindles in ipsilateral zones of the frontal cortex, whereas stronger single stimulation causes the diffuse generation of spindles in various parts of the neocortex. Besides this preferential unilateral effect, the influence of the posterior hypothalamus is found to be more strongly expressed in the frontal than in the occipital cortex. It is postulated that the posterior hypothalamus exerts its influence on the neocortex through the thalamic nuclei.

Animals↗
PubMedDate not supplied

Significance of emotional excitation in the mechanisms of spatial short-term memory in lower apes.

Correlates of variation in the level of emotional tension are studied in long-term experiments on adult monkeys. The simultaneous appearance of the electrodermal response and of a change in the heart rate is shown to reflect more accurately a rise in the level of emotional tension. Continuous recording of autonomic indexes reveals an increase in tension level during the presentation of conditioned signals and the performance of the motor response in the spatial delayed response test program. The emotiogenic structures are thought to influence the specific mechanisms of short-term memory during the presentation of conditioned signals and the performance of food-procuring instrumental behavior.

Animals↗