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Biomedical subjects

V G Kassil'

Publications and source records attributed to V G Kassil'.

At least 37 records · Page 2Linked to original sources
PubMed1987

[Changes in the signal significance of olfactory stimuli when coupled with negative experiences in young puppies].

A 5-min centripetal acceleration made the initially indifferent response to eucalyptus smell negative and the initially positive response to the mother smell uncertain in newborn puppies. The aversion to eucalyptus smell preserved longer than to the mother smell. Prolongation of the acceleration up to 15 min. increased the duration of olfactory aversion. The duration of aversion increases from 1st to 20th day but is quickly suppressed in 12-13-day old puppies due, apparently, to the interfering effects on the part of "young" analyzers (vision, hearing) involved in the control of behaviour during this period of ontogenesis. The prolonged preservation of the aversion occurs in infrequent presentation of olfactory stimuli not reinforced with rotation. Combining of feeding with subsequent rotation decreases the amount of consumed food which is essential for understanding of some cases of anorexia in children subjected to radial acceleration.

Acceleration↗
PubMed1987

[Electrophysiologic analysis of the nociceptive system of the thalamus in the ontogenesis of the rabbit].

In acute experiments in rabbits, characteristics of the parafascicular complex EPs in response to peripheral nociceptive stimulation revealed that the waveform of the EP changes during the ontogenesis: from a marked variability in newborn rabbits to a stable biphasic positive-negative potential in adult rabbits. During the postnatal period the magnitudes of the latency and duration of phases of the EPs decrease. "Critical periods" in the formation of the parafascicular complex have been discovered. The 1st period (7-8 days of age) is characterized by the largest amplitude and the shortest duration; the 2nd period (18-40-50 days) involves a stable form of the basic negative long phase. It has been established that, during the ontogenesis, the threshold of the nociceptive response rose.

Aging↗
PubMed1987

[Noradrenaline content of the brain of rats of various ages following adaptation to a new situation and to the development of a passive avoidance conditioned reflex].

Noradrenaline (NA) levels in cortico-striatal (including cerebral cortex, hippocamp, striatum) and hypothalamo-brainstem (including hypothalamus, thalamus, tectum + tegmentum) regions were determined by fluorometry in I- and 2-month-old male rats after 7-day adaptation to experimental conditions and passive avoidance learning by single electric foot shock. Neither the new environment nor a week's adaptation to it resulted in any significant alteration of NA content in both brain regions of 1- and 2-month-old rats. No considerable differences in NA levels were found in rats of both age groups with and without passive avoidance responses. But 24 hours after the exposure to foot shock NA basal levels markedly decreased in both brain regions of 1-month-old rats, while in 2-month-old ones NA basal levels markedly increased in hypothalamo-brainstem region.

Adaptation, Physiological↗
PubMed1986

[Role of smell in the food-seeking activity of newborn puppies].

In 36 newborn puppies, positive responses to the mother hair smell appear immediately after birth which indicates emanation of a corresponding pheromone. Within 6 hrs after isolation from the mother, the preference for her smell is reduced and substituted with a response to hair smell of other females. Learning of the motor to the mother smell seems to occur yet in prenatal period. The inherent negative response to cat's smell does not depend on the duration of the puppy isolation from the mother. During first 3 days of life (the 1st period), learning of the food-seeking response to an artificial smell is possible (imprinting). Starting from the 4th-5th day of life, the ability to form a food-seeking response to smell disappears. In 11-12 day old puppies, a conditioning can be achieved by means of combining smell with feeding 5-6 times. The role of olfaction in the puppy food-seeking behaviour during ontogenesis, is discussed.

Animals↗
PubMed1986

[Evoked potentials of the parafascicular complex of the rabbit thalamus during peripheral painful stimulation].

A systematic investigation of evoked potentials in the parafascicular complex of the thalamic nonspecific system has been carried out on rabbits. Two types of the evoked potentials were recorded due to the electrical skin stimulation of the paw. In the lateral part of the complex several fluctuations consisting of early and late positive-negative potentials following one another were recorded, in the medial--a simple positive-negative evoked potential. A more complex organization of the thalamic parafascicular complex of rodents is suggested.

Afferent Pathways↗
PubMed1984

[Function of the adrenal cortex during elaboration of the passive avoidance conditioned reflex in immature rats].

Plasma 11-hydroxycorticosteroid (11-OHCS) levels were measured in 30-day-old rats by fluorometry during passive avoidance (PA) learning by means of a single electric footshock. In contrast to the data obtained in adult animals, pre-exposure of young rats for 7 days to the experimental environment (over 3 min daily) resulted in elevation of the basal 11-OHCS levels and in the lack of distinct changes in the hormonal background after placing the young rats into a chamber. As in previous experiments on adult rats, one day after PA learning the 11-OHCS levels were significantly lower in young rats displaying PA than in the animals which did not exhibit PA behavior. Five days after PA training these differences in adrenocortical reactivity disappeared, as was the case in adult animals.

11-Hydroxycorticosteroids↗
PubMed1982

[Ontogenetic characteristics of the participation of the vagus nerves in regulation of the emotional state of dogs].

Bilateral supradiaphragmal section of the vagus nerves in 21 puppies and 12 adult dogs abolished adverse responses to selfstimulation of the lateral hypothalamus. The vagotomy led to facilitation (lowering of threshold, increase in the rate of leverpressing) of the self-stimulation of the posterior-lateral hypothalamic area which was most obvious and stable in the 8-12 week old puppies and adult dogs. When placing the electrodes in the anterior hypothalamic areas and related emotiogenic cerebral structures, the self-stimulation threshold increased. Therefore, the afferent effects on the vagus nerves can both inhibit and facilitate activity of the cerebral areas related to positive reinforcement and connected mainly with the posterior of anterior hypothalamic areas.

Animals↗
PubMed1982

[Adrenal cortical function in elaborating a passive avoidance conditioned reflex in rats adapted to experimental conditions].

Fluorometry was used to determine the content of 11-hydroxycorticosteroids (11-HCS) in the blood plasma of 2-month-old male rats in the course of passive avoidance learning by means of single electrocutaneous irritation (ECI) of the limbs. Pre-exposure of the animals for 7 days to experimental environment (over 3 min daily) led to a distinct reduction of the basal content of 11-HCS which returned to the initial level after adaptation discontinuance. One day after ECI the content of 11-HCS in rats which learned passive avoidance, was appreciably lower as compared to that in the animals which failed to learn the behavioral task. Five days after ECI the differences in the content of the corticosteroids in the animals of the two groups were little pronounced. It appears that while using passive avoidance as a long-term memory model, account should be taken of both the behavioral and emotional responses.

11-Hydroxycorticosteroids↗
PubMed1982

[Role of affective brain structures in regulation of the secretory function of the stomach].

The effects of self-stimulation (SS) of the brain reward sites on the gastric secretion were studied in 8 adult dogs with gastric fistula. The concentric (bipolar) electrodes were implanted in different sites of the brain reward system (hypothalamus, mamillary corpus, capsula interna, commissura grisea media, n. interstitialis striae terminalis, n. ventralis thalami, pes pedunculi cerebri) and then the instrumental reaction of the intracranial self-stimulation (ICSS) was induced. On recovery period normal acidity of the gastric juice was observed in 5 hungary dogs whereas in 3 hungry dogs the gastric acidity was significantly increased. In 3-5 min after the beginning of SS a lot of thick foamy slime and turbid juice was secreted. In dogs with initially normal pH of the gastric contents ICSS did not change it, whereas in dogs with increased pH ICSS made the gastric acidity normal pH of the gastric contents ICSS did not change it, whereas in dogs with increased pH ICSS made the gastric acidity normal. Bilateral supradiaphragmal vagotomy reduced the acidity in the animals of the last group, but only ICS made their pH quite normal. Therefore, positive emotional excitement associated with the stimulation of different areas of the brain reward system, makes gastric acidity normal and this reaction is not connected with the efferent systems of vagus nerves.

Animals↗
PubMed1980

[Interrelationship between the lateral hypothalamic self-stimulation reaction and the periodic motor activity of the stomach].

In 26 dogs, self-stimulation of the dorsal portion of the lateral hypothalamus at the level of anterior parts of ventromedial nuclei inhibits completely the stomach motor activity. Self-stimulation of the lateral portion of the middle hypothalamus at the level of posterior parts of ventro--medial nuclei does not affect at all the periodic contractions of the stomach. The intensity of self-stimulation depends on phase of the stomach periodic activity: during the contractions the number of lever-pressings is by 20% higher on the average than at resting. Bilateral supra-diaphragmal vagotomy increases the self-stimulation threshold in some animals and increases the number of lever--pressings in other animals at unaltered threshold.

Animals↗