Effects of endothelin and vasopressin on cerebral blood vessels.
Endothelin is a recently described peptide which has been suggested to be one type of endothelium-derived contracting factor. The goals of the present study were to examine the effects of endothelin and vasopressin on diameter of cerebral vessels and on permeability of the blood-brain barrier to fluorescein sodium (mol wt of 376). In anesthetized rats, topical suffusion of arginine vasopressin (10(-10) to 10(-7) M) decreased the diameter of pial arterioles, with a reduction of 27 +/- 1% at 10(-7) M in cerebrum and 35 +/- 2% at 10(-8) M for the basilar artery. A low concentration of endothelin (10(-10) M) produced modest (5 +/- 1%) dilatation of pial arterioles. Higher concentrations of endothelin (10(-8) and 10(-7) M) constricted pial arterioles with a reduction in diameter of 22 +/- 5% at 10(-7) M. Dilatation to endothelin was not observed in the basilar artery. The basilar artery constricted to lower doses of vasopressin than endothelin, but vasoconstriction to 10(-7) M endothelin (56 +/- 4%) was greater (P less than 0.05) than that for the same dose of vasopressin. Permeability of the blood-brain barrier to fluorescein sodium was not increased by vasopressin or endothelin. Thus 1) vasopressin produces constriction of brain blood vessels; 2) endothelin produces dilatation of pial arterioles at low doses but constriction at high doses; 3) constrictor responses to both peptides appear to be greater in the brain stem than in the cerebrum; and 4) vasopressin and endothelin do not increase permeability of the blood-brain barrier.
Faraci
F M
FM
Department of Internal Medicine, University of Iowa College of Medicine, Iowa City 52242.
D000818:Animals; D001127:Arginine Vasopressin / Q000494:pharmacology*; D001160:Arterioles / Q000187:drug effects; D001488:Basilar Artery / Q000187:drug effects; D002560:Cerebrovascular Circulation / Q000187:drug effects*; D004305:Dose-Response Relationship, Drug; D016232:Endothelins; D004730:Endothelium, Vascular; D008297:Male; D010455:Peptides / Q000494:pharmacology*; D010841:Pia Mater / Q000098:blood supply; D051381:Rats; D011919:Rats, Inbred Strains; D014661:Vasoconstriction / Q000187:drug effects
D016232:Endothelins; D010455:Peptides; D001127:Arginine Vasopressin