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J C Barillot

Publications and source records attributed to J C Barillot.

30 records · Page 2Linked to original sources
PubMed1976

[Activity of the expiratory laryngeal motor neurons].

The activity of the whole recurrent nerve branch to expiratory laryngeal muscles, along with unitary activity of fibres from this branch were studied in cats. Conduction velocities of fibres ranged between 19.5-93 m/s. We used two types of preparations: low "encephale isole " (at C7 level) cats with concomitant light Dial anesthesia or without any anesthesia, or cats deeply anesthetized with Dial or chloralose-urethane. The vagus nerves were preserved. Under normocapnic conditions, the delay of recruitment (i.e. the lag between the interruption of phrenic nerve activity and the start of unitary expiratory recurrent nerve activity) increases as the residual phrenic nerve activity increases; in fact, the delay is nearly zero with unanesthetized or lightly anesthetized preparations (small residual phrenic activity), but can extend up to 800 ms with deeply anesthetized preparations (large and long-lasting residual activity) (fig. 4). Recurrent nerve units show a maximum firing rate at the beginning of a discharge; the rate then decreases (fig. 5). The maximum frequency is strongly reduced when residual phrenic activity is present (fig. 7). The discharge duration does not reach the expiratory pause duration. Rapidly conducting fibres are the firs ones to cease activity (fig. 5)...

Action Potentials↗
PubMed1975

Activity of medullary respiratory neurones during reflexes from the lungs in cats.

We have studied in cats the discharge pattern in response to lung inflation and deflation of 283 medullary respiratory neurones, 173 being inspiratory and 110 expiratory. The ventral respiratory nucleus, near the nucleus ambiguus, was particularly investigated. The neurones were classified into bulbo-spinal neurones, laryngeal motoneurones and propriobulbar neurones by antidromic invasion from the spinal cord or the vagus nerve (collision test). The bulbo-spinal neurones responded in the same direction as spinal motoneurones in the Hering-Breuer reflexes: depression of inspiratory neurones and facilitation of expiratory neurones by inflation of the lungs. All the expiratory laryngeal motoneurones and some inspiratory laryngeal motoneurons responded in the opposite direction to the Hering-Breuer reflexes: depression of expiratory motoneurones and facilitation of inspiratory motoneurones. The function of propriobular neurones could be inferred from their response to Hering-Breuer reflexes: one group of propriobulbar neurones responded in such a manner as to be linked to the activity of the bulbo-spinal neurones; the other group responded in accordance with the activity of the laryngeal motoneurones.

Animals↗
PubMed1973

Anatomical and functional heterogeneity of the medullary respiratory neurons.

In a systematic study we attempted to activate the respiratory neurons antidromically by stimulating the spinal cord and the vagus. This has led to an anatomical and functional classification of the neurons: bulb-spinal neurons whose axons enter the spinal cord, vagal motoneurons, propriobulbar neurons which cannot be activated antidromically. We used simultaneously other tests (localization, response to Hering-Breuer reflexes or to cortical stimulation) which gave positive results. Two groups of respiratory neurons were apparent: a dorsal respiratory nucleus with only inspiratory bulbo-spinal neurons and a ventral respiratory nucleus with inspiratory and expiratory bulbo-spinal neurons, vagal motoneurons and propriobulbar neurons. The bulbo-spinal neurons and some propriobulbar neurons are normally related to Hering-Breuer reflexes evoked by lung inflation or deflation, but the recurrent laryngeal motoneurons or fibres and some propriobulbar neurons can give a paradoxical response to lung inflation. By cortical stimulation the propriobulbar neurons show only an arrest of their discharge, whereas the bulbo-spinal neurons give a burst of spikes followed by an inhibition. These results led to the following conclusions: (i) the propriobulbar neurons do exist; (ii) some neurons classified as medullary respiratory neurons have not really a ventilatory function: they belong to the laryngeal system; (iii) it is fundamental to use systematically the antidromic test and some other ones to know exactly the hodological situation of the neurons in the respiratory complex.

Animals↗
PubMedDate not supplied

Respiratory-related activity of the pharyngeal nerves in the rat.

In anesthetized (n = 26) or decerebrate (n = 15) rats, vagotomized, paralyzed and artificially ventilated, we recorded efferent respiratory-related discharges of nerves supplying the pharyngeal muscles, i.e. the glossopharyngeal nerve (IX; n = 30) and the pharyngeal ramus of the vagus nerve (PH.X; n = 33). In both types of preparation, all IX nerves fired during inspiration (I); most PH.X fired either during I (n = 11), expiration (E, n = 12), or both phases (n = 4); some of them were continuously active, without any respiratory modulation (n = 6). We also examined the timing of inspiratory pharyngeal bursts in relation to the phrenic (inspiratory) bursts. We found that the burst onset occurred significantly earlier in pharyngeal nerves than in phrenic ones (pharyngeal-to-phrenic delay). In anesthetized animals, this pharyngeal-to-phrenic delay was long enough to reveal that inspiratory activity appeared first on IX, then on PH.X, and then on phrenic nerves. Since hypoxia did not significantly alter the pharyngeal-to-phrenic delay, we conclude that a reliable organization of the inspiratory drive on pharyngeal and diaphragmatic muscles should exist, in the rat.

Animals↗