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Atypical β‐adrenoceptors in the rat isolated common carotid artery
Author(s) -
Oriowo Mabayoje Ayotunde
Publication year - 1994
Publication title -
british journal of pharmacology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.432
H-Index - 211
eISSN - 1476-5381
pISSN - 0007-1188
DOI - 10.1111/j.1476-5381.1994.tb17049.x
Subject(s) - isoprenaline , salbutamol , propranolol , schild regression , medicine , endocrinology , artery , agonist , vascular smooth muscle , carotid arteries , smooth muscle , chemistry , stimulation , receptor , asthma
1 The possible existence of atypical β‐adrenoceptors in vascular smooth muscle of the rat common carotid artery was examined in this study. 2 Isoprenaline produced concentration‐dependent relaxation of noradrenaline (10 −7 m ) precontracted ring segments of the carotid artery. The relaxation was not affected by endothelial denudation. 3 Propranolol (10 −8 m ‐3 × 10 −7 m ) shifted the isoprenaline curve to the right without suppressing the maximum response. However, the slope (0.74) of the Schild plot was significantly ( P < 0.05) less than 1. 4 Salbutamol (fe), CGP 12177 and BRL 37344 (ft) also concentration‐dependently relaxed noradrenaline precontracted artery segments. These relaxations were not affected by propranolol (10 −7 m ). Pretreatment of the artery segments with BRL 37344 did not desensitize the tissue to the relaxant effect of isoprenaline, CGP 12177 and salbutamol. 5 It is concluded that atypical β‐adrenoceptors exist in vascular smooth muscle of the common carotid artery.