Pressor response to endothelin in guinea pigs.
Endothelin (ET), an endothelium-derived vasoconstrictor peptide, was injected into the jugular vein (i.v.) of guinea pigs anesthetized with urethane. Blood pressure was measured from a cannula inserted into the carotid artery. All experiments were carried out after treatment with adrenergic and cholinergic antagonists. ET showed a potent, dose-dependent pressor action in guinea pigs. However, the initial, transient depressor response which is observed in rats was not produced in guinea pigs. Nicardipine (0.1 mg/kg), a dihydropyridine Ca2+-channel blocker, significantly inhibited the ET-induced pressor response. These results suggest that ET causes a potent pressor response, which appears to be related to the activation of Ca2+ channels.
Li
L
L
Department of Pharmacology, University of Tsukuba, Ibaraki, Japan.
Ishikawa
T
T
Miyauchi
T
T
Yanagisawa
M
M
Kimura
S
S
Goto
K
K
Masaki
T
T
D000818:Animals; D001794:Blood Pressure / Q000187:drug effects*; D004305:Dose-Response Relationship, Drug; D016232:Endothelins; D006168:Guinea Pigs; D006339:Heart Rate / Q000187:drug effects; D008297:Male; D009529:Nicardipine / Q000494:pharmacology; D010455:Peptides / Q000494:pharmacology*
D016232:Endothelins; D010455:Peptides; D009529:Nicardipine