Influences d'origine cardio-vasculaire et respiratoire sur l'activit� somatique

Dell, Paul C.

doi:10.1007/bf01227378

Cited by 10 publications

(1 citation statement)

References 27 publications

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“…Thus the carotid sinus baroreceptors have direct access to the ascending and descending reticular systems known to exercise control of somatic motor excitability. There is good evidence (Dell & Bonvallet, 1966) that cells in the medical reticular formation, close to the anterior pole of the tractus solitarius, are the origin of potent ascending inhibitory influences. For example, stimulation of this region in cats produces synchronization of the electrocorticogram and a state resembling sleep (Magnes, Moruzzi & Pompeiano, 1961) (effects which call to mind Koch's experiments in the dog (1932)) whereas destruction by coagulation produces excitement and insomnia (Jouvet, 1968).…”

Section: Discussionmentioning

confidence: 99%

Prolonged inactivation of cortical pyramidal tract neurones in cats by distension of the carotid sinus

Coleridge¹,

Coleridge²,

Rosenthal³

1976

The Journal of Physiology

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SUMMARY1. We have investigated the effects of stimulating carotid sinus baroreceptors upon the activity of single cortical pyramidal tract cells (PTcells) in anaesthetized cats.2. Extracellular potentials were recorded from PT-cells, which were driven orthodromically (1/sec) by stimulating thalamic nuclei (N. ventralis lateralis, N. ventralis posterolateralis) or afferent nerves in the contralateral forepaw. Baroreceptors were stimulated by inflating small balloons placed in the bifurcations of one or both common carotid arteries.3. Distension of the carotid sinus caused a prolonged depression of the orthodromically evoked discharge of eighteen of thirty-two PT-cells, the effect ranging from a 15 % reduction in firing to complete cessation of activity (average reduction, 39 %). The depression of firing outlasted the period of balloon inflation by an average of 85 see; in some experiments inhibition persisted for as long as 2-3 min.4. Inflation of the balloon caused a reflex fall in arterial pressure (mean decrease, 29 mmHg), pressure reverting to the control level as soon as the balloon was deflated. Single fibre recording from the carotid sinus nerve confirmed that stimulation was confined to baroreceptors and that carotid chemoreceptors were unaffected by balloon distension.5. Depression of PT-cell activity could not be explained simply by a fall in cerebral blood flow resulting from the reflex fall in arterial blood pressure. When a comparable or greater degree of hypotension was produced by bleeding or peripheral vagal stimulation, PT-cell firing fell in a third of experiments but reverted immediately to the control level when arterial pressure was restored. Thus some factor other than a decrease in H. M. COLERIDGE AND OTHERS cerebral perfusion pressure was responsible for the prolonged inhibition evoked by carotid sinus distension.6. Our results are consistent with the hypothesis that baroreceptor input to the reticular formation exerts an ascending influence on cortical mechanisms, with prolonged inhibitory effects comparable to those previously demonstrated at spinal level.

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Section: Discussionmentioning

confidence: 99%