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At least 19 recordsLinked to original sources
PubMed1990

[The descending pathways of the medial nuclei of the respiratory center to the respiratory muscles].

Electrical activity of the phrenic, external and internal intercostal nerves was studied in anesthetized cats during electrical stimulation of the inspiratory "points" of the reticular gigantocellular nucleus (medial zone of the respiratory center). Structural characteristics of reflex responses of phrenic and intercostal nerves to stimulation of various respiratory and nonrespiratory bulbar sites as well as their respiratory modulation, were analyzed. The organisation of probably neurophysiological mechanism of phrenic and intercostal responses to stimulation of the medial nucleus of the respiratory center, is discussed.

Animals↗
PubMedDate not supplied

Involvement of reticular neurons of the cat medulla oblongata in the integrative activity of the respiratory center.

Reticular neurons of the respiratory center are divided into three groups. One group is located in the medial zone of the center and receives afferent spike activity from structures of the respiratory apparatus and chemoreceptors. Another is located in the inspiratory and expiratory areas of the respiratory center, and takes part in integrating signals and activating the effector mechanisms of the center. The third group is found in both zones of the center and organizes its effector activity. Electrical stimulation of medulla oblongata nuclei could transform reticular neurons of the lateral zone of the center into respiratory neurons. Evidence for this was obtained in the form of short-latency and long-latency evoked potentials in reticular neurons.

Animals↗
PubMed1986

Prenatal and postnatal maturation of medullary 'respiratory centers'.

During infancy respiratory patterns change with maturation. However, there is no documentation of the development of the neurons thought to be related to respiratory control. Relevant neurons in the medulla oblongata were examined using Golgi impregnation methods. Dendritic spines increased prenatally and decreased postnatally in the medullary respiratory centers (i.e., dorsal vagal nucleus, nucleus tractus solitarii and reticular formation). The prenatal neuronal maturation is earlier in the reticular formation than the vagal nucleus. These changes in neuronal dendrites may be related to the development of central respiratory control and the occurrence of primary apnea in prematurity and sleep apnea in sudden infant death syndrome.

Humans↗
PubMed1988

[The respiratory center--the regulator of the respiratory system].

The authors consider the respiratory centre to be the regulator of the respiratory system and to consist of 3 main functional blocks: chemoregulator, respiratory rhythm autogenerator and mechanoregulator, functions of which are provided by the neurons of medulla oblongata. The main aim of chemoregulator block is to maintain the level of ventilation volume speed, which is necessary to compensate the difference between the signals of setting and the firing from the chemoreceptors. The main aim of mechanoregulator block is to provide the functioning of the regulation loop of the respiratory muscles comparing the signals which come from the respiratory autogenerator, and the firing of the mechanoreceptors. The generator unit of the respiratory centre is a set of rhythm-forming associations, the system of 4 neurons (early and late inspiratory and expiratory) are typical among them. The neurons are connected by recurrent inhibitory bonds: the neuron of each rhythm-forming group, successively becoming excited, inhibits the two preceding neurons in the cycle; for all this the neuron of the successive group is released from inhibition and in such a way the rhythmogenesis occurs. The respiratory centre forms a common unit for chemo- and mechanoreceptor loops, through which the circuits of feedback for both loops are connected, providing the regulation of breathing.

Animals↗
PubMed1983

[Significance of the corpus callosum in the paired activity of the respiratory center].

The asymmetrical reactions of respiratory neurons of the right and left halves of the respiratory center and varied changes in bioelectrical activity of external intercostal muscles on both sides of the chest were discovered in experiments on anesthetized cats in response to successive electrical stimulation of the symmetrical cortical areas of the right and left cerebral hemispheres before and after callosotomy. It was demonstrated that callosotomy increased on both sides of the respiratory center the quantity of neurons responsive to ipsilateral cortical stimulation and determined the character of the asymmetrical reactions of right and left respiratory neurons and intercostal muscles. On the basis of the data obtained it is concluded that the corpus callosum contributes to the functional integration of both halves of the respiratory center.

Animals↗
PubMed1981

[Correction of respiratory disorders by electric stimulation of various structures of the respiratory center].

Impulse activity of respiratory neurones and respiration during electric stimulation of the inspiratory and expiratory sites of the respiratory center was studied in cats anesthetized with nembutal. The study was made with an object of imposing a new rhythm on these sites and of recovering respiratory function. It has been established that stimulation of the inspiratory and expiratory sites of the giganto-cellular nucleus and of some structures of the solitary tract nucleus enables one to impose the new rhythm on the respiratory neurones of the ventral and respiratory nuclei and on respiration as well as to renew the respiration arrested.

Animals↗
PubMed1980

[Reciprocal connections of respiratory center nuclei].

The reactions of 181 respiratory neurons of solitary and ambiguous nuclei were studied on 64 cats in the course of stimulation of inspiratory and expiratory zones of gigantocellular nuclei. A study was also made of the reactions of 224 reticular and 9 respiratory neurons of these zones during stimulation of solitary and ambiguous nuclei. Various reactions were recorded in response to the stimulation. Therefore the nuclei of the respiratory center possess various information. In the course of stimulation of the gigantocellular nucleus there predominated an increase in the neuronal electrical activity. On the contrary, inhibition of respiratory and reticular neurons of the gigantocellular nucleus was predominant in the course of stimulation of solitary and ambiguus nuclei. It is suggested that the interactions described underlie the formation of circular rhythms of respiratory center stimulation.

Animals↗
PubMed1990

[Respiratory regulation during neuronal hyperactivation of the respiratory center].

The responses of breathing and of respiratory neurons to microinjections of penicillin into the respiratory center area were studied in anesthetized and spontaneously breathing rats. The injections caused different alterations of the respiration, of the activity of respiratory neurons and their spatial distribution, and initiated respiratory moments of apneustic and gasping types. the hyperactivation of the respiratory center neurons by penicillin seems to cause a reversible development of pathological types of respiration.

Animals↗
PubMed1982

[Compensatory reactions of the respiratory center and their manifestations at the periphery of animals with respiratory tract and lung injuries].

The microelectrode and stereotaxic techniques were used in experimental injuries to the respiratory tract and lungs to demonstrate that the respiratory center (RC) was in a state of enhanced excitation whatever the focus of injury. It was found that the efferent flow of impulses from the RC was not uniformly manifested by electrical activity of the respiratory muscles. In tracheitis, the respiration was effected by the inspiratory and expiratory muscles but remained of the diaphragmal type. Considerable reserve possibilities of the RC compensation were discovered in response to additional adequate stimulants. In unilateral pneumonia, the electrical activity of the diaphragm and that of different groups of the expiratory muscles were found to be enhanced, whereas the respiration became of the diaphragmal-abdominal type. The compensatory reactions of the RC were unchanged. In grave bilateral injuries to the lungs, the main factors having a stimulant action on the RC were additional resistance to the respiration and developing hypoxemia. At the same time there was a decrease in the electrical activity of the respiratory muscles. There is every reason to believe that the decline in the electrical activity of the respiratory muscles serves an important protective reaction of the body in grave lung injuries.

Abdominal Muscles↗
PubMed1975

Occlusion pressure as a measure of respiratory center output in conscious man.

The output of the "respiratory centers" has been estimated by measuring ventilation, inspiratory muscle power, EMG of the diaphragm, and by various other means, each of which has serious disadvantages. The static pressure generated by the inspiratory muscles at FRC against an obstructed airway is here suggested as a useful alternative. Ten conscious, normal, sitting human subjects were subjected to CO2 rebreathing (Read, 1967) and their airways were occluded at end-expiration at intervals without the subjects being aware in advance. The inspiratory pressure waves so generated were found to be distorted by conscious or unconscious responses to the occlusion which had a minimum latency of 0.15 sec. The pressure generated at 0.1 sec after the onset of inspiration (P0.1) was nevertheless easy to measure and was reproducible in each subject. The CO2 response obtained by plotting P0.1 against PCO2, was curvilinear, the P0.1 increasing more rapidly at high PCO2. The P0.1 is independent of pulmonary mechanics. Since it measures the rate of rise of inspiratory activity and not the peak activity it is also independent of mechanisms that alter the respiratory pattern by affecting inspiratory duration, in particular the vagal volume-related inspiratory-inhibitory reflex. It is concluded that measurements of P0.1 represent a useful index of the output of the respiratory centers.

Airway Obstruction↗
PubMed1983

Effects of aminophylline on respiratory center and reflex activity in premature infants with apnea.

Fourteen preterm infants with apnea (body weight, 1052 +/- 44 g; gestational age, 30.2 +/- 0.5 wks; and postnatal age, 9.9 +/- 1.5 days) were studied in an effort to evaluate the effects of aminophylline on respiratory center output and respiratory reflex activity in the preterm infant with idiopathic apnea. This was done by using the airway occlusion technique. The infants were studied before and 48 h after aminophylline was begun as a treatment for apnea. Occlusion pressure, which reflects respiratory center output, was measured at 100 msec after occlusion started (P100) and at its maximum (Pmo). P100 increased from 2.4 +/- 0.2 to 3.1 +/- 0.2 cmH2O (P less than 0.005), and Pmo from 6.1 +/- 0.7 to 8.8 +/- 1.0 cmH2O (P less than 0.001) after aminophylline therapy was started. The % prolongation of inspiratory time during the occluded breaths, when compared to the unoccluded breaths increased from 26.2 +/- 10.6 to 55.8 +/- 12.5% (P less than 0.01). This reflects a significant increase in the strength of the Hering Breuer reflex. Effective elastance, a measure of respiratory load compensation, was significantly higher during aminophylline treatment. It increased from 1.09 +/- 0.14 to 1.33 +/- 0.14 cmH2O/ml (P less than 0.02).

Aminophylline↗