RESUMEN
Comparative microelectrophysiological study of character and peculiarities of effects of the cortical nucleus of amygdala and of the periamygdalar area of pyriform cortex on impulse activity was performed on the same single functionally identified respiratory medullar neurons. A high reactivity of bulbar respiratory neurons on stimulation is established in both studied limbic structures. There is established the qualitatively different character of their response reactions at stimulation of the cortical amygdala nucleus and the periamygdalar cortex. The cortical amygdala nucleus has been shown to produce on the activity of medullar respiratory neurons both facilitating and inhibitory action with predominance of the activating one (without topographical orderliness). The effect of periamygdalar cortex at stimulation of various parts was characterized by topographic differentiation. The suppressing reactions of neurons in the majority of cases were recorded at stimulation of the rostral area of periamygdalar cortex, whereas the excitatory reactions--at stimulation of its caudal part. Functional organization of respiratory control of the studied limbic system structures is discussed.
Asunto(s)
Amígdala del Cerebelo/fisiología , Neuronas/fisiología , Respiración , Amígdala del Cerebelo/citología , Animales , Gatos , Neuronas/citologíaRESUMEN
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.
Asunto(s)
Sistema Límbico/fisiología , Neuronas/fisiología , Reflejo/fisiología , Vísceras/inervación , Vías Aferentes/fisiología , Animales , Vías Eferentes/fisiología , Electrofisiología , Giro del Cíngulo/fisiología , Vísceras/fisiologíaRESUMEN
Effects of high frequency stimulation of the amygdala central nucleus involved a selective decrease in the activity: an increase in the activity of the inferior cardiac nerve and a simultaneous decrease in the activity of the vertebral nerve, as well as an obvious BP increase. Bilateral electrolytic lesions of the same amygdala structure accompanied with an overload of the higher nervous activity induced no hypertensions. The role of the amygdala central nucleus in control of cardiovascular functions is discussed.
Asunto(s)
Amígdala del Cerebelo/fisiología , Fenómenos Fisiológicos Cardiovasculares , Animales , Presión Sanguínea , Gatos , Condicionamiento Operante/fisiología , Vasos Coronarios/inervación , Estimulación Eléctrica , Electroencefalografía , Electrofisiología , Hipertensión/etiología , Hipertensión/fisiopatología , Médula Espinal/fisiología , Estrés Fisiológico/complicacionesRESUMEN
Effects of high frequency stimulation of dorsal and ventral regions of anterior area 25 of the limbic cortex on the tonic electrical activity of two postganglionic sympathetic nerves of stellate ganglion-inferior cardiac and vertebral nerves and arterial blood pressure were studied in anesthetized cats. It was revealed three types of medullary influences: generalized activation of both sympathetic nerves and pressor responses mainly in case of stimulation of ventral structures, generalized inhibition of electrical activity of both sympathetic nerves and depressor responses in case of stimulation of dorsal region of area 25 and selective modulation of activity, namely increase in activity of inferior cardiac nerve and simultaneous decrease of activity of vertebral nerve. According to data of our previous comparative studies of sympathetic responses of inferior and vertebral postganglionic nerves to stimulation of anterior and posterior hypothalamus as a working hypothesis it is supposed that the dorsal region of area 25 of limbic cortex is the analogy of trophotropic system of anterior hypothalamus, the ventral region--of ergotrophic system of posterior hypothalamus.
Asunto(s)
Sistema Límbico/fisiología , Inhibición Neural , Neuronas/fisiología , Sistema Nervioso Simpático/fisiología , Transmisión Sináptica , Vísceras/inervación , Animales , Gatos , Vías Eferentes/fisiología , Estimulación Eléctrica , Ganglios Simpáticos/fisiología , Potenciales de la Membrana/fisiologíaRESUMEN
Effects of i.v. administration of N- and M-cholinergic blocking agents ganglerone and atropine and alpha- and beta-adrenergic blocking agents phentolamine and obsidan (propranolol) on reaction of desynchronisation of EEG and on autonomic reactions (arterial blood pressure, heart and respiratory rates) evoked by low- and high frequency stimulation of the posterior hypothalamus were studied in hens. It was shown that atropine induces a pharmacological dissociation of ascending and descending influences of the hypothalamus by blocking the desynchronizing mechanisms of the upward discharge of the hypothalamus without any apparent changes of autonomic reactions. It was found that the effects of adrenoblocking agents are diametrically opposite to that of atropine in regard to the EEG component, as well as the autonomic components of hypothalamically induced activation reaction. Peculiarities of evolutionary development of neurochemical structures of ascending and descending systems of the hypothalamus are discussed.
Asunto(s)
Sistema Nervioso Autónomo/fisiología , Hipotálamo Posterior/fisiología , Prosencéfalo/fisiología , Animales , Atropina/farmacología , Sistema Nervioso Autónomo/efectos de los fármacos , Benzoatos/farmacología , Presión Sanguínea/efectos de los fármacos , Pollos , Sincronización Cortical/efectos de los fármacos , Sincronización Cortical/instrumentación , Sincronización Cortical/métodos , Electrodos Implantados , Electrofisiología , Femenino , Frecuencia Cardíaca/efectos de los fármacos , Hipotálamo Posterior/efectos de los fármacos , Parasimpatolíticos/farmacología , Fentolamina/farmacología , Propranolol/farmacología , Prosencéfalo/efectos de los fármacos , Respiración/efectos de los fármacosRESUMEN
Studies have been made of the effect of stimulation of the anterior and posterior hypothalamus on the electrical activity of the hemispheres, arterial blood pressure, heart and respiration rates. Mainly desynchronizing mechanisms were revealed in the ascending influences from both the anterior and posterior hypothalamus. Concerning the descending influences, it was found that stimulation of the anterior hypothalamus evokes depressor reactions, whereas stimulation of the posterior hypothalamus results in pressor reactions. Peculiarities of evolutionary development of the ascending and descending mechanisms of the posterior and anterior hypothalamus are discussed.