Endothelium-dependent vasorelaxation induced by L-carnitine in isolated aorta from normotensive and hypertensive rats.
The aim of this work was to investigate the mechanism of the vasodilatory effect induced by L-carnitine. Relaxation produced by L-carnitine was studied in rat aortic rings with and without functional endothelium, pre-contracted with phenylephrine by adding cumulative doses of L-carnitine (10(-7) to 10(-3) M). The relaxation evoked by L-carnitine reached higher values in aortic rings from spontaneously hypertensive rats than those obtained in arteries from normotensive rats; no relaxation was produced in de-endothelialized arteries. However, in the presence of N(G)-nitro-L-arginine (3 x 10(-5) M, a nitric oxide synthase inhibitor), Ro 68070 (10(-4) M, a thromboxane synthetase inhibitor-thromboxane A2/prostaglandin H2 receptor antagonist) or ICI 192605 (10(-5) M, a thromboxane A2 receptor antagonist) the relaxant response to L-carnitine was significantly inhibited. These results show that L-carnitine induced endothelium-dependent relaxation in the rat aorta and the mechanism of this relaxation appeared to be mostly mediated by endothelial production of nitric oxide but#10; also could involve prevention of the action of cyclooxygenase endothelial products acting on the thromboxane A2/prostaglandin H2 receptor.
Herrera
María Dolores
MD
Department of Pharmacology, Faculty of Pharmacy, University of Seville, C/ Profesor García González s/n, 41012-Seville, Spain. herrera@fafar.us.es
Bueno
Rosario
R
De Sotomayor
María Alvarez
MA
Pérez-Guerrero
Concepción
C
Vázquez
Carmen M
CM
Marhuenda
Elisa
E
D000818:Animals; D001013:Aorta, Thoracic / Q000187:drug effects*; D002331:Carnitine / Q000494:pharmacology*; D004146:Dioxanes / Q000494:pharmacology; D004730:Endothelium, Vascular / Q000502:physiology*; D004791:Enzyme Inhibitors / Q000494:pharmacology; D006973:Hypertension / Q000503:physiopathology*; D066298:In Vitro Techniques; D008297:Male; D009126:Muscle Relaxation; D009131:Muscle, Smooth, Vascular / Q000502:physiology*; D019001:Nitric Oxide Synthase / Q000037:antagonists & inhibitors; D052250:Nitric Oxide Synthase Type III; D019335:Nitroarginine / Q000494:pharmacology; D011448:Prostaglandin Antagonists / Q000494:pharmacology; D011453:Prostaglandins / Q000502:physiology; D051381:Rats; D011918:Rats, Inbred SHR; D011921:Rats, Inbred WKY; D013930:Thromboxane-A Synthase / Q000037:antagonists & inhibitors; D014664:Vasodilation / Q000187:drug effects*
D004146:Dioxanes; D004791:Enzyme Inhibitors; D011448:Prostaglandin Antagonists; D011453:Prostaglandins; C057498:ICI 192605; D019335:Nitroarginine; D019001:Nitric Oxide Synthase; D052250:Nitric Oxide Synthase Type III; C496316:Nos3 protein, rat; D013930:Thromboxane-A Synthase; D002331:Carnitine