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Biomedical subjects

D Payen

Publications and source records attributed to D Payen.

At least 91 records · Page 5Linked to original sources

[Vascular smooth muscle fibers and the autonomic nervous system].

Vascular Smooth Muscle cell (V.S.M.C) plays a major role in the regulation of vasomotion. Sympathetic system play a key role in vascular smooth muscle function. Epinephrine (humoral pathway) and norepinephrine (nervous pathway) can both stimulate V.S.C.M. via delta and beta adrenergic receptors. The function of parasympathetic system is more controversial. Acetylcholine induces the release of a relaxing factor by the endothelial cell (E.D.R.F.) but it has a direct contracting effect on V.S.C.M. Neural vasodilation is also concerned by noradrenergic mechanisms.

Autonomic Nervous System↗

Head injury: clonidine decreases plasma catecholamines.

Seven patients who had suffered head injury 3 to 5 days before the study was undertaken received clonidine (2.5 micrograms/kg iv over 10 min). This resulted in a reduction of plasma norepinephrine (p less than .05) and in normalization of plasma epinephrine (p less than .05). Neither common carotid blood flow nor diastolic blood flow as index of global cerebral perfusion as measured by pulsed Doppler changed. The reduction of sympathetic overactivity, probably due to the specific action of clonidine on alpha 2-adrenoceptors within the rostral ventrolateral medulla, may be of interest in the management of head injury because of the maintenance of cephalic hemodynamics.

Acute Disease↗