Endothelin-1 induces potent constriction of lymphatic vessels in situ.
The response of lymph vessels, arterioles and venules in the exteriorized rat mesentery to endothelin-1, vasopressin and norepinephrine was examined with the aid of high-resolution television microscopy. On a molar basis, endothelin-1 was more potent than vasopressin to contract the three types of vessels. Norepinephrine, which could constrict blood microvessels, did not act on lymph vessels. Acetylcholine, sodium-nitroprusside and isoproterenol were ineffective to block the constrictive responses of lymph vessels to endothelin-1 and vasopressin. At the same concentrations, however, acetylcholine and sodium-nitroprusside antagonized the responses of arterioles and venules to endothelin-1 and norepinephrine, whereas the responses of blood microvessels to vasopressin remained unaffected. Isoproterenol, at doses capable of blocking the response of the arterioles and venules to norepinephrine, did not interfere with the constriction induced by endothelin-1 and vasopressin on these vessels. It is suggested that endothelin-1 might play a role in the regulation of lymphatic contractility apart from its vasoconstrictor activity on blood vessels.
Fortes
Z B
ZB
Department of Pharmacology, Institute of Biomedical Sciences, University of São Paulo, Brazil.
Scivoletto
R
R
Garcia-Leme
J
J
D000818:Animals; D004305:Dose-Response Relationship, Drug; D016232:Endothelins; D066298:In Vitro Techniques; D008208:Lymphatic System / Q000187:drug effects*; D008297:Male; D008833:Microcirculation / Q000187:drug effects; D009131:Muscle, Smooth, Vascular / Q000187:drug effects; D009638:Norepinephrine / Q000494:pharmacology; D010455:Peptides / Q000494:pharmacology*; D051381:Rats; D011919:Rats, Inbred Strains; D013152:Splanchnic Circulation / Q000187:drug effects*; D014661:Vasoconstriction / Q000187:drug effects*; D014667:Vasopressins / Q000494:pharmacology
D016232:Endothelins; D010455:Peptides; D014667:Vasopressins; D009638:Norepinephrine