[Current data of the membrane receptors of the vascular smooth muscle fibers].
The cell membrane of vascular smooth muscle is lined with many receptor sensitive to signals emitted by the vessel wall or transported in the blood stream. Recent data on the mechanisms by which these receptors regulate vascular tone enable them to be classified into two main groups. The first group includes the receptors carried by the membrane proteins which are under their direct control; ATP-P2x receptors on Na+ and Ca2+ channels, pharmacological receptors (dihydropyridines, diltiazem, phenylalkylamines) situated on a voltage operated channel, receptors to cromakaline-like substances associated with a potassium channel, receptors to atriopeptines (ANF-B) with guanylate cyclase activity. The second group of receptors act through the intermediary of the G protein (which has a high affinity for guanylic nucleotides); it regulates the activity of an effector which may be an enzyme or an ionic channel. The receptors of this type which have been identified in vascular smooth muscle are: --positively (beta-adrenergic, DA1-dopaminergic, P1 purinergic or H2-histaminic) or negatively coupled (alpha 2-adrenergic) to adrenylate cyclase; --positively coupled to C phospholipase (angiotensin II, vasopressin V1, 5-H-T2, alpha 1-adrenergic, M1-cholinergic, H1-histaminic). In addition, the same receptor may act by different mechanisms (V1-vasopressin, alpha 2-adrenergic, for example). Whatever the initial mechanism of action, all these receptors influence the contraction by changing ionic permeability or by producing secondary relaxing (cyclic AMP, cyclic GMP) or contractility messengers (inositol phosphates, diacylglycerol).(ABSTRACT TRUNCATED AT 250 WORDS)
Stoclet
J C
JC
Université Louis Pasteur de Strasbourg, URA CNRS 0600, faculté de pharmacie, Illkirch.
D002450:Cell Communication / Q000502:physiology; D002462:Cell Membrane / Q000502:physiology*; D006801:Humans; D008565:Membrane Proteins / Q000502:physiology*; D009131:Muscle, Smooth, Vascular / Q000166:cytology*; D011956:Receptors, Cell Surface / Q000502:physiology*
D008565:Membrane Proteins; D011956:Receptors, Cell Surface
Données récentes sur les récepteurs membranaires de la fibre musculaire lisse vasculaire.