Influence of hypertension on tetrahydropapaveroline-induced vasorelaxation in rat thoracic aorta.
Tetrahydropapaveroline (THP), a condensation product of ethanol-derived acetaldehyde, has been shown to elicit a vasorelaxant response in rat thoracic aorta. This study examined the influence of hypertension on the THP-induced vasorelaxant responsiveness. Ring segments of thoracic aorta were isolated from Wistar-Kyoto (WKY) and spontaneously hypertensive rats (SHR) and isometric tension development was measured with a force transducer. In aorta, with or without intact endothelium, the contractile responses to potassium chloride (0-120 mM) were comparable between the WKY and the SHR groups. Hypertension did not affect the vasoconstrictive response to norepinephrine (0-10 microM) in vessels with intact endothelium, whereas it attenuated the norepinephrine-induced response in vessels without endothelium. THP (0.1-100 microM) elicited endothelium-intact as well as -denuded vasorelaxation in aorta from both WKY and SHR groups. Interestingly, the THP-induced endothelium-dependent vasorelaxation was significantly enhanced, whereas the THP-induced endothelium-independent vasorelaxation was not affected by hypertension. These data indicate that the THP-induced endothelium-dependent vasorelaxant response is altered by the hypertensive state.
Department of Biology, Morgan State University, Baltimore, MD 21251, USA.
Ricardo A
RA
Brown
Karl J
KJ
Ilg
Jun
J
Ren
D000818:Animals; D001013:Aorta, Thoracic / Q000187:drug effects / Q000503:physiopathology*; D004730:Endothelium, Vascular / Q000503:physiopathology; D006973:Hypertension / Q000503:physiopathology*; D008297:Male; D009119:Muscle Contraction / Q000187:drug effects; D009126:Muscle Relaxation / Q000187:drug effects*; D009131:Muscle, Smooth, Vascular / Q000187:drug effects / Q000503:physiopathology; D009638:Norepinephrine / Q000494:pharmacology; D011189:Potassium Chloride / Q000494:pharmacology; D051381:Rats; D011918:Rats, Inbred SHR; D011921:Rats, Inbred WKY; D013765:Tetrahydropapaveroline / Q000494:pharmacology*; D014661:Vasoconstriction / Q000187:drug effects
D013765:Tetrahydropapaveroline; D011189:Potassium Chloride; D009638:Norepinephrine