RESUMEN
We studied the influence of stimulation of the CA1 and CA3 areas of the hippocampus on the impulse activity of respiratory neurons (RN) of the medulla oblongata under normal and oxygen deficiency conditions. Under conditions of normal atmospheric pressure, the electrical stimulation of the CA1 and CA3 areas of the hippocampus had mainly an inhibiting influence. In the initial phase, at a 4-5-thousand meter altitude, activation of frequent discharge of neurons occurred. In this situation, stimulation of the CA1 and CA3 areas was more accentuated than under conditions of normoxia. In the second phase (an altitude of 7.5-8 thousand meters), on the reduction of the impulse activity of neurons, stimulation of the CA1 and CA3 areas of the hippocampus induced untypical responses of these neurons.
Asunto(s)
Hipocampo/fisiopatología , Hipoxia/fisiopatología , Neuronas , Centro Respiratorio/fisiopatología , Transmisión Sináptica , Animales , Hipocampo/patología , Hipoxia/patología , Ratas , Centro Respiratorio/patologíaRESUMEN
The pulse activity of medullar respiration center neurons and rat's respiration as a function of excitation of the lateral mammillary (LM) nucleus of the hypothalamus were studied in differing hypoxic conditions. Electrical stimulation of the LM nucleus in normoxia had a predominantly activating effect. A moderate pO2 fall at the start of "ascent" to 4000-5000 m increased pulsation of the respiratory neurons. On this background the activating effect of LM nucleus stimulation was less pronounced as compared to normoxia although it still prevailed over inhibition. The alleviating effect of LM nucleus stimulation was particularly evident with a sharp inhibition of respiratory neurons caused by critical oxygen deficiency at the highest altitude (7500-8000 m). After the "descent" to the normal atmospheric pressure the spontaneous rhythmic activity of rat's neurons and reaction to stimulation gradually recovered baseline values.
Asunto(s)
Potenciales de Acción/fisiología , Área Hipotalámica Lateral/fisiopatología , Hipoxia/fisiopatología , Bulbo Raquídeo/fisiopatología , Neuronas/patología , Oxígeno/metabolismo , Centro Respiratorio/fisiopatología , Animales , Modelos Animales de Enfermedad , Área Hipotalámica Lateral/metabolismo , Área Hipotalámica Lateral/patología , Hipoxia/metabolismo , Hipoxia/patología , Bulbo Raquídeo/metabolismo , Bulbo Raquídeo/patología , Consumo de Oxígeno , Ratas , Centro Respiratorio/patologíaRESUMEN
Effects of locus coeruleus (LC) stimulation on the impulse activity of bulbar respiration neurons in rats were studied on a background of varying hypoxia. Different levels of hypoxia were used as an experiment model for ensuing summation of the LC effect. At the normal atmospheric pressure, LC electrical stimulation had an alleviating and also inhibiting effect on the impulse activity of these medulla neurons; however, the former effect was dominant. During the initial hypoxia simulating the altitude of 4000-5000 m, LC stimulation had a weak alleviating effect. On this level of hypoxia such effect is highly important, as unchecked strengthening of respiration activating mechanisms may result in excessive hyperventilation and consequent respiration slowing down to standstill because of low blood content of carbonic acid. During heavy hypoxia simulating the altitude of 7500-8000 m LC electrical stimulation had an intrinsic to this structure activating effect on markedly inhibited respiratory neurons. In the event of acute hypoxia the highly sensitive cortical component lose their inhibitory effect on the bulbar respiratory center and suprabulbary formations. However, this favours startup of the activating systems and enhancement of the respiration ventilatory function.
Asunto(s)
Respiración de la Célula/fisiología , Hipoxia/patología , Hipoxia/fisiopatología , Locus Coeruleus/fisiopatología , Bulbo Raquídeo/fisiopatología , Neuronas/patología , Respiración , Centro Respiratorio/fisiopatología , Potenciales de Acción/fisiología , Enfermedad Aguda , Animales , Masculino , RatasRESUMEN
Three-month decreased voluntary optimum respiration rate (DVORR) trainings during therapeutic exercises in students with various abnormalities caused increases in vital capacity and chest circumference amplitude. DVORR also affected cardiovascular performance. During exercises, heart rate decreased and pulse pressure increased, suggesting economized cardiac performance and better myocardial function. The use of this method in the students reduces morbidity, improves health, and increases physical fitness and progress in studies.
Asunto(s)
Ejercicio Físico/fisiología , Educación y Entrenamiento Físico/métodos , Aptitud Física/fisiología , Respiración , Estudiantes , Adolescente , Adulto , Femenino , Estudios de Seguimiento , HumanosRESUMEN
Injection of adrenergic and cholinergic agents to animals in the normal athmospheric conditions did not tigger drastic changes on the electric activity of the brain and heart. Acutehipoxia demands high adaptability from the body. In such conditions stimulation of reticular formation and hypothalamus produces different changes in the EEG and ECG activity whith injecting adrenergic and cholinergic agents. It was determined that cholinergic influence are effective in the regulation of electrical brain activity while adrenergics are more important for the realization of descending influences of the truncus cerebri vegetative centers and are less active in the modulation of the cerebral cortex activity.
Asunto(s)
Adrenérgicos/farmacología , Encéfalo/efectos de los fármacos , Colinérgicos/farmacología , Corazón/efectos de los fármacos , Animales , Encéfalo/fisiología , Encéfalo/fisiopatología , Electrocardiografía , Electroencefalografía , Electrofisiología , Corazón/fisiología , Corazón/fisiopatología , Hipoxia , ConejosRESUMEN
The paper reports the effects of alpha and beta-adrenergic substances on the cardiac rhythm and electrical activity of the brain under the hypoxic conditions. beta-adrenergic substances were shown to have a stronger influence on these parameters as compared with alpha-adrenergic. The neoepinephrine effects were pronounced before "lifting", while the propranolol effects increased "at the altitude". Neopinephrine was found to have a stimulating effect on the cerebral cortex under the conditions of hypoxia.
Asunto(s)
Agonistas Adrenérgicos/farmacología , Antagonistas Adrenérgicos beta/farmacología , Corteza Cerebral/fisiopatología , Electroencefalografía/efectos de los fármacos , Frecuencia Cardíaca/efectos de los fármacos , Hipoxia/fisiopatología , Animales , Corteza Cerebral/efectos de los fármacos , Modelos Animales de Enfermedad , Epinefrina/farmacología , Frecuencia Cardíaca/fisiología , Hipoxia/tratamiento farmacológico , Propranolol/farmacología , ConejosRESUMEN
The structures of limbic system have great integration in vegetative reactions. In the oxygen deficiency conditions we studied influence of irritation of limbical cortex, orbitofrontal cortes, hipotalamys, septum and hippocampus (CA1 and CA3 areas) on the impulse activity of respiratory neurons. Phases of hypoxia were the model of experiment. Irritation some of this structures on normoxia and 4-5 thousand meters higher, we discover inhibiting influense on respiratory neurons; some structures irritation had activating influence. In difficult conditions of hypoxia (7.5-8 thousand meters) on the reduction of the impulse activity of neurons, stimulation induced uncharacteristic reactions. Those different reactions of irritation limbic structures have regulation sense on respitatory neurons.
Asunto(s)
Hipoxia/fisiopatología , Sistema Límbico/fisiopatología , Sistema Respiratorio/inervación , Animales , Electrofisiología , Neuronas/fisiología , Ratas , Sistema Respiratorio/fisiopatologíaRESUMEN
In the oxygen deficiency conditions, we studied influence of irritation of ventral (BNST), lateral (LSN) and medial (MSN) nuclei of the septum on the impulse activity of the bulbar respiratory neurons and on respiration. Phases of hypoxia were the model of experiment. In conditions of normal atmospheric pressure, the electrical stimulation of BNST, LSN and MSN nuclei of the septum exerted inhibiting as well as activating influence with the inhibiting influence prevailing. In difficult conditions of hypoxia (7.5-8 thousand meters) on the reduction of the impulse activity of neurons, stimulation of septum nucleuses induced uncharacteristic reactions of those neurons.
Asunto(s)
Hipoxia/fisiopatología , Bulbo Raquídeo/fisiopatología , Núcleos Septales/fisiopatología , Potenciales de Acción , Animales , Estimulación Eléctrica , Bulbo Raquídeo/citología , Neuronas/fisiología , Ratas , Respiración , Centro Respiratorio/citología , Centro Respiratorio/fisiopatologíaRESUMEN
Different breathing pathologies (apneusis, gasping, Cheyne-Stokes breathing and Kussmaul breathing) were observed in anaesthetized rabbits and rats exposed to hypoxia at the altitude of 7500-8000 meters. Dominance of the high-voltage slow EKG activity (the delta-wave type) suggested deterioration of the brain functioning. Registration of impulse activities of the inspiration and expiration breathing neurons in medulla oblongata revealed a higher tolerance of the inspiration neurons to severe hypoxia which is attributed to the metabolic specifics and functional heterogeneity of these neurons. Character of the neuron impulsation is indicative of the reflectory effects of hemo- and mechanoreceptors, and the direct effects of different humoral substances resulting in impairment of the central control of pacemakers and breathing pathologies. It appears that various breathing pathologies in altitude chambers and mountains are triggered by the hypoxic factor. However, no dependence was established either between the initial breathing rhythm (before "ascent") and various types of breathing at the "altitude" or these types of breathing and magnitude of hypoxia.
Asunto(s)
Hipoxia Encefálica/fisiopatología , Trastornos Respiratorios/fisiopatología , Respiración , Enfermedad Aguda , Animales , Tronco Encefálico/fisiopatología , Electrocardiografía , Electroencefalografía , Hipoxia Encefálica/diagnóstico , Mecanorreceptores/fisiopatología , Conejos , RatasRESUMEN
In the normal as well as in the oxygen deficiency conditions the research has been conducted to study the influence of associative mediodorsal (MD) nucleus of thalamus on impulsive activity of respiratory neurons of medulla oblongata of respiration. In conditions of normal atmospheric pressure, before the uplift of the animals, the electrical stimulation of MD of nucleus of thalamus has had mainly inhibiting influence. In the initial phase, on 4-5 thousand meter altitude, activation of frequent discharge of neurons occurred, the respiration has become frequent as well. In this situation the inhibiting influence of stimulation of MD nucleus of thalamus was more accentuated than in conditions of normoxia. In the second phase, 7.5-8 thousand meters, the opposite occurred, i.e. reduction of respiratory center activity of medulla oblongata and thalamus. In this difficult conditions of hypoxia, a reduction of impulsive activity of neurons has been observed; the respiration was becoming slower and surface. Meanwhile, the inhibiting influence of thalamus was not significant.
Asunto(s)
Hipoxia/fisiopatología , Bulbo Raquídeo/fisiología , Neuronas/fisiología , Fenómenos Fisiológicos Respiratorios , Núcleos Talámicos/fisiología , Altitud , Animales , Estimulación Eléctrica , Electrofisiología , Hipoxia/patología , Bulbo Raquídeo/patología , RatasRESUMEN
In the normoxic conditions, prior to the "ascent" of rabbits, the i.v. injection of M-choline blocking benactyzine slowed down the ECG rhythm already within the next few minutes. Irritation of the reticular formation against this background did not initiate the reaction of activation; yet, heart rate was essentially unaltered by benactyzine. This was ascribed to low effectiveness of the benactyzine M-cholinergic mediation with respect to the cardiac function in contrast to the electric activity of the brain cortex due to, apparently, the abundance of M-choline receptors in this structure. The effect of N-cholinolytic ganglerone on the spontaneous and induced cortical activities was weak and, as compared with benactyzine, more expressed upon the heart rate. These choline blockers combined with hypoxia and the benactyzine-produced slow ECG waves on the initial phase (4000-5000 m) brought about neither spontaneous nor induced by the reticular formation irritation activation of ECG. At the maximal "altitude" (8500-9000 m) the benactyzine-synchronized ECG rhythm tended to become deeper assuming the low delta-type activity observed at the same "altitude" without i.v. benactyzine. With this ECG, irritation of Dieters' formation was impotent to trigger the reaction of activation.
Asunto(s)
Encéfalo/fisiología , Frecuencia Cardíaca/fisiología , Hipoxia/metabolismo , Receptores Muscarínicos/metabolismo , Receptores Nicotínicos/metabolismo , Animales , Benactizina/farmacología , Benzoatos/farmacología , Modelos Animales de Enfermedad , Electrocardiografía/efectos de los fármacos , Electroencefalografía/efectos de los fármacos , Frecuencia Cardíaca/efectos de los fármacos , Hipoxia/fisiopatología , Antagonistas Muscarínicos/farmacología , Parasimpatolíticos/farmacología , Conejos , Receptores Muscarínicos/efectos de los fármacos , Receptores Nicotínicos/efectos de los fármacos , Formación Reticular/efectos de los fármacos , Formación Reticular/metabolismo , Formación Reticular/fisiopatologíaRESUMEN
The response of bulbar respiratory neurons and the total inspiration to stimulation of the limbic cortex and hypothalamus was not identical as a result of different sensitivity of the studied structures. The hypothalamus exerts mainly facilitating influence both in norm and at the maximal altitude (7500-8000 m). The limbic cortex exerts mainly inhibitory influence. At the maximal altitude no typical reactions of the respiratory neurons and the total respiration were observed in response to stimulation.
Asunto(s)
Hipotálamo/fisiología , Hipoxia/fisiopatología , Sistema Límbico/fisiología , Bulbo Raquídeo/fisiología , Neuronas/fisiología , Respiración/fisiología , Centro Respiratorio/fisiología , Enfermedad Aguda , Altitud , Animales , Cámaras de Exposición Atmosférica , Estimulación Eléctrica , Microelectrodos , RatasRESUMEN
In normoxia, the orbitofrontal cortex and thalamic mediodorsal nucleus (MDN) basically inhibit the pulse activity of bulbar respiratory neurons and respiration in general. During initial hypoxia (4,000-5,000 m) a slight reduction of PO2 in the inspired air increases excitability of all the brain structures including those under study. However, strengthening of the orbitofrontal cortex and MDN inhibitory effect was leveled down by activizing brain structures, and the direct exciting effect of reduced PO2 on peripheral and central chemoreceptors. As a result, respiration became hurried in that period. Still, this inhibitory effect appears to play a positive role too. Unobstructed enhancement of activizing neural and humoral regulators of respiration might have led to intense hyperventilation fraught with an opposite action, i.e., inhibition, if not arrest of respiration consequent to reduced PO2 blood level, etc. Under acute hypoxia (7.5,000-8,000 m), oxygen deficit brings about inhibition, of all the brain structures including the orbitofrontal cortex and MDN. Moderation of their inhibitory effect in this period also plays an important role as it stimulates liberation of activizing systems and a relative increase in the ventilatory function of respiration.
Asunto(s)
Lóbulo Frontal/fisiopatología , Hipoxia/fisiopatología , Neuronas/fisiología , Respiración/fisiología , Centro Respiratorio/fisiopatología , Núcleos Talámicos/fisiopatología , Animales , Células Quimiorreceptoras/fisiopatología , Estimulación Eléctrica , Potenciales Evocados , Lóbulo Frontal/patología , Hipoxia/patología , Bulbo Raquídeo/patología , Bulbo Raquídeo/fisiopatología , Neuronas/patología , Ratas , Centro Respiratorio/patología , Núcleos Talámicos/patologíaRESUMEN
Stimulation of the orbito-frontal cortex inhibited activity of bulbar expiratory, inspiratory and reticular (non-respiratory) neurons. The first phase of hypoxia generated facilitatory influence of cerebral activating structures, whereas the second phase led to a contrary effect (depression). Subcortical activating structures, however, retained some of their facilitatory influence thus maintaining the oxygen homeostasis of the organism.
Asunto(s)
Lóbulo Frontal/fisiología , Hipoxia/fisiopatología , Bulbo Raquídeo/fisiología , Neuronas/fisiología , Respiración/fisiología , Centro Respiratorio/fisiología , Potenciales de Acción/fisiología , Animales , Estimulación Eléctrica/métodos , Electrodos Implantados , Inhibición Neural/fisiología , Ratas , Técnicas EstereotáxicasRESUMEN
Complex action of hypoxia and electrostimulation of the limbic cortex on unit activity of bulbar respiratory neurons was studied. Under normal barometric pressure the influence of the limbic electrostimulation on activity of bulbar respiratory neurons was ambiguous, i.e., both activation and inhibition were observed, but inhibitory influences prevailed. In initial phase (4000-5000 m) at the background of hypoxic activation the influence of electrostimulation of the limbic cortex on activity of respiratory neurons was predominantly inhibitory, as under conditions of normoxia. In the phase of severe hypoxia (7500-8000 m) at the background of expressed hypoxic suppression of activity of respiratory neurons stimulation of the limbic cortex did not induce reactions characteristic of these neurons. Reaction of the respiratory neurons on the electrical stimulation of the limbic cortex in different phases of hypoxic action depended on relatively high sensitivity to hypoxia of the limbic cortex and the functional state of the bulbar respiratory center.
Asunto(s)
Hipoxia/fisiopatología , Sistema Límbico/fisiopatología , Bulbo Raquídeo/fisiopatología , Neuronas/fisiología , Centro Respiratorio/fisiopatología , Potenciales de Acción/fisiología , Altitud , Animales , Cámaras de Exposición Atmosférica , Estimulación Eléctrica/métodos , RatasRESUMEN
Investigations into the role of the hypothalamus nuclei (dorsomedial and posthypothalamic) and amygdala (cortical and central) in regulation of impulse activity of medullary respiratory neurons and respiration as a whole revealed: a) phasic changes of there exponents in hypoxia; b) variety effect of excitation (activation, inhibition) due to stimulation of the structures. At the initial stage of hypoxia (the altitude of 4000-5000 m) hypoxic activation of the impulse discharge made moderating effect of stimulation more expressed as compared with the initial stage of hypoxia. At maximal altitudes (7500-8000 m) inhibition of respiratory neurons occurred and respiration grew slow and superficial. It is noteworthy that on this background stimulation of hypothalamus and amygdala caused more marked moderating effect when compared with the initial stage. This is apparently associated with disengaging of inhibitory effects of cortex on subcortical structures and increased influence of limbic structures on the bulbar respiratory center.
Asunto(s)
Altitud , Amígdala del Cerebelo/fisiología , Hipotálamo/fisiología , Hipoxia/fisiopatología , Bulbo Raquídeo/fisiología , Neuronas Aferentes/fisiología , Respiración/fisiología , Animales , Modelos Biológicos , RatasRESUMEN
Under atmospheric pressure, stimulation of amygdala induced an activating effect on the medullary respiratory and reticular neurons. At the initial stage of hypoxia (altitude 4000-5000 metres), against the background of hypoxic activation of the firing rate, facilitating influence of tetanic stimulation of the amygdala was lesser even though prevailing over its inhibiting action. At the maximal altitude (7500-8000 m), against the background of hypoxic suppression of unit activity, the stimulation of amygdala exerted mainly an activating effect. The response was particularly obvious in the neurons with low spontaneous activity.
Asunto(s)
Amígdala del Cerebelo/fisiología , Hipoxia/fisiopatología , Bulbo Raquídeo/fisiología , Neuronas/fisiología , Centro Respiratorio/fisiología , Animales , Estimulación Eléctrica , Electrodos Implantados , RatasRESUMEN
Under normal conditions of atmosphere pressure the electrical stimulation of hypothalamus induced activating influence on the medullary respiratory and reticular neurons. At the initial stage of the hypoxia (the altitude 4500-5000 m), against the background of hypoxic activation of firing rate, facilitating influence of tetanic stimulation of hypothalamus was lesser though it prevailed over its inhibiting action. At the maximal altitude (8000-9000 m), against the background of hypoxic depression of unit activity, the stimulation of hypothalamus exerted mainly a stimulating effect. That response was particularly obvious in the neurons with low spontaneous activity.
Asunto(s)
Hipotálamo/fisiopatología , Hipoxia/fisiopatología , Bulbo Raquídeo/fisiopatología , Neuronas/fisiología , Respiración , Enfermedad Aguda , Altitud , Animales , Estimulación Eléctrica , Potenciales Evocados , Microelectrodos , Ratas , Centro Respiratorio/fisiopatologíaRESUMEN
The authors have demonstrated the estradiol induction of the key glycolytic enzymes of the brain (hexokinase, phosphofructokinase and pyruvate kinase) which is "switched off" by injection of actinomycin-D--an inhibitor of protein biosynthesis. Another steroid hormone, progesterone, has an inhibitory action on the above enzymes. Administration of estradiol to rats significantly elevates the amplitude and frequency of contractility induced in them, while the same doses of progesterone decrease them. Thus, there is a definite correlation between the induction of glycolytic enzymes and sensitivity toward contractility on the one hand and the estradiol/progesterone ratio on the other. It is possible that activation of glycolysis may reduce the threshold of epileptic attacks providing an additional energy for epileptic manifestations.
Asunto(s)
Encéfalo/fisiopatología , Estradiol , Glucólisis , Progesterona , Convulsiones/fisiopatología , Animales , Encéfalo/enzimología , Inducción Enzimática , Femenino , Hexoquinasa/metabolismo , Fosfofructoquinasa-1/metabolismo , Piruvato Quinasa/metabolismo , RatasRESUMEN
The changes of respiratory neurons (RS) activity had a phasic character in acute hypoxia. At the initial stage of the hypoxia (the altitude 4000-5000 m), the firing rate of inspiratory (IN) and expiratory (EN) neurons was increasing whereas at the maximum altitude (8000-9000 m) it was decreasing. After the descent, the background RN activity restored. The comparative analysis of RN resistance to hypoxia showed higher resistance of IN than of EN which determined the entire reaction of the respiratory system, viz. the more stable phase of inspiration. A great number of IN were revealed at the altitude of 8000-9000 m which had been in the state of inhibition for a long time under conditions of normoxia but became activated with the acute oxygen deficiency.