Endothelium-dependent relaxation of the rat renal artery caused by activation of histamine H1-receptors.
The response of the isolated renal artery to histamine was analysed. The renal artery in relaxed state did not respond to histamine. However, in the precontracted renal artery with phenylephrine, histamine (10(-8)-10(-4) mol/l) caused a concentration-dependent relaxation. Removal of the vascular endothelium abolished the relaxant response to smaller concentrations of histamine (10(8)-3 x 10(-6) mol/l), and strongly reduced that to large concentrations of histamine (greater than 3 x 10(-6) mol/l). Mepyramine abolished the former response, and strongly reduced the latter response. The slight relaxant effect of histamine, resistant to mepyramine and removal of endothelium, was blocked only after combined treatment with mepyramine and metiamide. Sotalol, atropine, indometacin and diethylcarbamazine did not suppress the inhibitory effect of histamine. It is concluded that the relaxant effect of histamine on the rat renal artery is predominantly mediated by activation of H1-receptors on the endothelial cells. Only a slight component of the relaxant response to large concentrations of histamine results from activation of both H1- and H2-receptors in smooth muscle of the artery. Cyclo-oxygenase products of arachidonic acid metabolism are not involved in the mediation of the relaxant response to histamine.
Krstić
M K
MK
Department of Pharmacology, Faculty of Medicine, Belgrade, Yugoslavia.
Stepanović
R M
RM
Krstić
S K
SK
Katusić
Z S
ZS
D000109:Acetylcholine / Q000494:pharmacology; D000818:Animals; D004730:Endothelium, Vascular / Q000502:physiology*; D005260:Female; D006632:Histamine / Q000494:pharmacology; D066298:In Vitro Techniques; D007213:Indomethacin / Q000494:pharmacology; D008297:Male; D009119:Muscle Contraction / Q000187:drug effects; D009131:Muscle, Smooth, Vascular / Q000502:physiology*; D010656:Phenylephrine / Q000494:pharmacology; D051381:Rats; D011969:Receptors, Histamine H1 / Q000502:physiology*; D012077:Renal Artery / Q000187:drug effects
D011969:Receptors, Histamine H1; D010656:Phenylephrine; D006632:Histamine; D000109:Acetylcholine; D007213:Indomethacin