Open Accessα1-Adrenoceptor Subtype Mediates Norepinephrine-Induced Contraction of the Rabbit Isolated Ovarian Artery
Author(s) -
Oriowo Ma,
Bevan Ja
Publication year - 1987
Publication title -
journal of cardiovascular pharmacology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.762
H-Index - 100
eISSN - 1533-4023
pISSN - 0160-2446
DOI - 10.1097/00005344-198709010-00030
Subject(s) - phentolamine , prazosin , yohimbine , phenylephrine , medicine , endocrinology , norepinephrine , epinephrine , vascular smooth muscle , clonidine , contraction (grammar) , adrenergic receptor , artery , chemistry , propranolol , antagonist , smooth muscle , blood pressure , receptor , dopamine
The interactions between selective alpha-adrenoceptor agonists and antagonists were studied in the rabbit isolated ovarian artery in an attempt to characterize the alpha-adrenoceptor subtype present in the smooth muscle of this vessel. Norepinephrine, epinephrine, and phenylephrine, but not clonidine or BHT-920, contracted the ovarian artery in a concentration dependent manner. The rank order of potency was epinephrine greater than norepinephrine greater than phenylephrine. The contractions were competitively antagonized by prazosin, phentolamine, and yohimbine. However, prazosin and phentolamine were approximately 100-500 times more potent than yohimbine against norepinephrine and phenylephrine. Observations were unchanged when arterial segments were used after endothelial removal. Norepinephrine-induced contractions of the ovarian artery were relatively resistant to blockade by diltiazem. The results suggest that exclusively alpha 1-adrenoceptors are present in vascular smooth muscle cells of the ovarian artery, whose activation operates through a mechanism relatively independent of Ca2+ influx into the smooth muscle cells.