[The contribution of the schools of L. A. Orbeli and V. N. Chernigovskiĭ to the development of the physiology of the autonomic nervous system].
Explore the source record for details and available documents.
Animals↗
Biomedical subjects
K G Bagdasarian
Publications and source records attributed to K G Bagdasarian.
[Comparative study of the discharges of sympathetic and parasympathetic nerves during stimulation of the visceral field of the limbic cortex].
Comparative characteristics of parasympathetic responses in pelvic nerve and sympathetic responses in lumbar white communicating rami to stimulation of dorsal and ventral parts of anterior, visceral area of limbic cortex were studied in anesthetized and immobilized cats. Single shocks or short trains of stimuli of the area 25 in limbic cortex evoked a complex response in pelvic nerve, consisting mostly of three waves: the late waves II and III of the parasympathetic discharge with a mean latency of 63.3 and 180.4 msec, and a mean magnitude of 11.0 and 16.7 microV, resp. A short latency component was rarely observed and its latency was about 15.9 msec. The EPs in pelvic nerve and white rami had the lowest threshold in stimulation of the ventral part of area 25. Comparative study of the excitability-recovery properties of cingulo-parasympathetic and cingulo-sympathetic responses revealed a long-lasting inhibition of the test responses for 2000 and 900 msec, resp.
Action Potentials↗
[Parasympathetic discharges of the pelvic nerve during stimulation of different hypothalamic structures].
The characteristics of evoked responses in pelvic nerve elicited with electrical stimulation of posterior, tuberal, anterior hypothalamus and preoptic area were studied in anesthetized and immobilized cats. The complex response in pelvic nerve consisted of waves I, II, III with latencies from 13 to 28, 52 to 96, 113 to 256 msec, resp. The evoked responses of lowest thresholds and shortest latencies were obtained from the posterior hypothalamus. These data suggest that hypothalamic parasympathoactivating neurons are localized mostly in the posterior hypothalamus. After high frequency (100/sec, 10-sec. period) stimulation of posterior and anterior hypothalamus which produced blood pressure increase, the mean component of pelvic discharge--wave III was depressed during the whole period of the pressure reaction, the inhibition being of baroreflex origin. Early components of the discharges after tetanic stimulation of hypothalamus were facilitated. Paired stimulation of the hypothalamus demonstrated that nearly 2.5 sec were required for complete recovery of the evoked test-responses in pelvic nerve.
Animals↗
[Comparative study of sympathetic and parasympathetic discharges in the autonomic nerves during stimulation of different structures of the cat hypothalamus].
Simultaneous recordings of hypothalamo-parasympathetic and hypothalamo-sympathetic evoked discharges in anesthetized cats demonstrated that both parasympathetic discharges in the pelvic nerve and sympathetic discharges in the splanchnic nerve of the lowest threshold and shortest latency could be obtained from stimulation of the posterior hypothalamus. The focus of the maximal neuronal activated elicited by stimulation of afferent fibres of visceral nerves and the focus evoking maximal efferent reactions of parasympathetic and sympathetic nerves were located in the same region of the postero-lateral hypothalamus. It is supposed (as a working hypothesis) that convergent polysensory neurons of the hypothalamus are also polyeffector divergent elements of the hypothalamo-visceral reflex system.
Action Potentials↗
[Evoked hypothalamic potentials from the pelvic nerve].
Comparative electrophysiological analysis of EPs in the posterior, tuberal and anterior hypothalamus to electrical stimulation of the pelvic nerve was performed in anesthetized and immobilized cats. The focus of maximal activity was revealed in the postero-lateral hypothalamus. "Visceral" responses of the hypothalamus evoked by the pelvic nerve stimulation had a long recovery cycle and were suppressed at a low-frequency stimulation. These findings suggest a poly-synaptic organization of the projection of pelvic afferent systems in the hypothalamus.
Afferent Pathways↗
[Reactions of hypothalamic neurons to stimulation of the pelvic and sciatic nerves].
Unit activity of posterior, tuberal and anterior parts of the hypothalamus was studied during stimulation of the pelvic nerve in anesthetized and immobilized cats. Comparative analysis showed that neurons of the posterior hypothalamus were more responsive (89.6%) and had a shorter mean latency (33.3 +/- 2.4 msec) than neurons of more rostral parts of the hypothalamus. The focus of maximal pelvic-induced unit activity seems to be located in the posterior hypothalamus. The unit responses of the posterior hypothalamus evoked by pelvic nerve stimulation had long recovery cycles and were suppressed at low frequencies of stimulation. These findings suggest a polysynaptic organization of pelvic afferent projection in the hypothalamus. A high degree of convergence of the visceral and somatic afferent signals onto single neurons was found during stimulation of pelvic and sciatic nerves. The functional role of neurons of integrative types is discussed.
Afferent Pathways↗
[Projections of the visceral and somatic afferent systems to identified neurons of the supraoptic nucleus].
Antidromic identification of the hypothalamic supraoptic nucleus' neurosecretory cells in cats in the course of stimulation of the posterior hypophysis aided to study the possibility and degree of modulation of the unit activity by ascending visceral and somatic afferent signals during stimulation of the splanchnic and sciatic nerves. the data obtained revealed that the major part of the neurosecretory neurons cannot be activated by means of the afferent signals. The projections of visceral and somatic afferent systems represented by the splanchnic and sciatic nerves, spread over to the nonroendocrinal cells of the hypothalamic supraoptic nucleus. The functional role of peripheral afferents in modulation of the hypothalamic neuroendocrinal neurons activity, is discussed.
Afferent Pathways↗
[Microelectrophysiologic analysis of the representation of different groups of afferent splanchnic nerve fibers in structures of the posterior and anterior hypothalamus in the cat].
Explore the source record for details and available documents.
Action Potentials↗
[Convergence of visceral afferent impulsation on hypothalamic neurons following stimulation of the vagus and splanchnic nerves].
Responses of single hypothalamic units to stimulation of the vagal, splanchnic and sciatic nerves and to photic stimulation were studied in anaesthetized, curarized cats. Most of the reactive neurons of the posterior and anterior hypothalamus responded to stimulation of vagus and splanchnicus. The pattern of responses of these polysensory units reactive in most cases to sciatic nerve and (or) photic stimulation too, were mainly unidirectional, nonreciprocal and excitatory in case of stimulation of visceral afferents of parasympathetic and sympathetic nerves. Absence of reciprocal responses to stimulation of "antagonistic" autonomic nerves and predominance of "convergence" units with polysensory inputs suggest that the electrical reaction of most of posterior as well as anterior hypothalamic neurons are of nonspecific "reticular" type.
Animals↗
[Reactions of the neurons of the anterior and posterior regions of the hypothalamus to light stimulation and stimulation of the splanchnic and sciatic nerves].
Responses of single hypothalamic neurons to splanchnic, sciatic nerves and photic stimulation were studied in anesthetized, curarized cats. It is found that units of the posterior and anterior hypothalamus are "convergence neurons" with multisensory inputs. Convergence of somatosensory and visceral (splanchnic) impulses to such neurons was complete. No neurons responding only to the splanchnic nerve stimulation were found. In the posterior hypothalamus some units responded only to stimulation of splanchnic and sciatic nerves and were unresponsive to a flash. On the contrary, in the anterior hypothalamus a part of units responded only to photic stimulation. The polysensory neurons of the posterior and anterior hypothalamus were of a nonspecific modality: they responded with a similar pattern of phasic or tonic discharge with a predominance of phasic responses. Units were more often excited than inhibited. A high responsibility (68%) of spontaneously active neurons to somato-visceral and photic stimulation was observed in the posterior, as well as in the anterior hypothalamus. The principles of functional organization of hypothalamic afferent system are discussed.
Animals↗
[The neuronal organization of the limbic (cingulo-)-visceral reflex arc].
The paper summarizes new electrophysiological data concerning the structural-functional organization of the limbic cortex and role of the rostral limbic region of visceral functions. Here are presented the results of a series of electrophysiological investigation of the focus of localization in the supracallosal (area 24) and infracallosal (area 25) part of the anterior cingulate gyrus of evoked potentials of maximal amplitude and minimal latent period to stimulation of pelvic, splanchnic and sciatic nerves. It was shown that evoked potentials of maximal amplitude and minimal latent periods to stimulation of viscero-somatic nerves are recorded in the supragenual area 24 in comparison with the infragenual area 25 of the anterior limbic cortex. In a series of microelectrophysiological studies of reactions of neurons of area 24 and 25 it was established that the reactivity of neurons of area 24 is higher than that of area 25. All these data indicate to the leading role of area 24 in reception and treatment of viscero-somatic afferent signals. In series of experiments it was shown that the focus of exciting neurons, forming the descending singular-autonomic discharge is localized in the infragenual area 25 of anterior limbic cortex. In a study of the comparative characteristics of sympathetic responses in lumbar white communicating rami and parasympathetic responses in pelvic nerve it was shown that evoked potentials in pelvic nerve and white rami had the lowest threshold and shorter latency in case of stimulation of area 25. Study of characteristics of influence of dorsal (area 24) and ventral (area 25) regions of rostral limbic cortex on bioelectrical activity of two postganglionic sympathetic nerves-inferior cardiac and vertebral branches of stellate ganglion, innervating coronary vessels and vessels of anterior extremities correspondingly, showed that stimulation of ventral area 25 evoked increase of electrical activity of the two sympathetic nerves and reliable increase of systemic arterial pressure, while stimulation of dorsal area 24 evoked decrease of tonic activity of the two sympathetic nerves and reliable decrease of systemic arterial pressure. In the paper are presented also the results of microelectrophysiological investigation of peculiarities of reactions of inspiratory and expiratory neurons of bulbar respiratory center to high frequency stimulation of area 24 and 25--in case of stimulation of dorsal area 24 the prevailing effect is suppression of spike activity of neurons, of stimulation of ventral, infragenual area 25 the prevailing influence is excitatory. In another series of microelectrophysiological experiments it was shown downward blocking inhibitory influence of dorsal supragenual area 24 of anterior limbic cortex on activity of vagal viscerosensory neurons of bulbar solitary tract nucleus. It is concluded that the strictly connected one another areas 24 and 25 of limbic cortex are functionally differentiated: the infra-limbic cortex is mainly a viscero-motor cortex, while the prelimbic area 24 plays a leading role in reception and treatment of viscero-somatic afferent information.
Afferent Pathways↗
[The neuronal organization of the amygdala-visceral reflex arch].
The paper summarizes the histomorphic, histochemical, autoradiographic, immune-histochemical and electrophysiological data on the structural-functional organization of the amygdalar complexes. While discussing the problem of neuron organization of the afferent and efferent groups in the amygdala-visceral arch the authors present their data of microelectrophysiological studies of the specific amygdala neuron reactions in response to stimulation of the vagus, ventric, and sciatic nerves, and of the second somatic sensor cortex zone. It was observed that interoceptive impulsation reaching the polysensor neurons of the central, corticomedial, and basolateral groups of the amygdala complex nuclei have no significant qualitative differences. A series of experiments demonstrated that the polysensor convergent amygdala neurons are also polyeffectoral. Comparative studies of the sympathetic discharges in the white connecting branches produced by stimulation of the above nuclear amygdala groups, confirmed absence of a clear topographic localization of the sympatho-activating structures within an amygdala. Comparative exploration of the parasympathetic discharges in the pelvis nerve discovered a discharge of complex configuration in response to simulation of the pelvis nerve nuclei. There was no notable topographic localization of the amygdala parasympathoactivating structures. The system's arterial pressure was studied in response to stimulation of various amygdala structures. Low-frequency stimulation (5 Hertz) of all amygdala structures produces depressor reactions, high-frequency stimulation (100 Hertz) produces pressor reactions. Microelectrophysiological data are provided on the specific reactions of the inspiration and expiration neurons of the bulbar respiratory centre under frequency stimulation of various amygdala structures. The authors have concluded that the bulbar-spinal mechanisms regulating the vegetative functions are implemented by polysensoral-polyeffectoral integrative amygdala neurons of the convergent-divergent type. Consequently, there are no separate populations of the sympatho-activating and parasympathoactivation neurons and of the selective structures regulating the respiratory and the cardiovascular functions.
Amygdala↗