The influence of 17-beta-oestradiol and the natural oestrous cycle on alpha-adrenoceptor-mediated responses of the cardiovascular system in the rat.
The effect of 17 beta-oestradiol pretreatment and the natural oestrous cycle on responses of rat cardiac and vascular alpha-adrenoceptors was investigated. It was found that treatment with the oestrogen had no effect on cardiac adrenoceptor sensitivity, while pretreatment with the hormone caused a significant increase in vascular alpha 2-, but not vascular alpha 1-adrenoceptor responsiveness. Pressor responses of pithed rats to selective alpha 1- or alpha 2-adrenoceptor agonists did not alter, however, during the natural oestrous cycle. These findings suggest that changes in oestrogen levels are capable of altering alpha-adrenoceptor-mediated vascular responses but that the relatively small changes in oestrogen which may occur throughout the natural oestrous cycle do not appear to alter the responses of these vascular alpha-adrenoceptors.
Austin
C
C
Physiological Laboratory, University of Liverpool, UK.
Chess-Williams
R
R
D000316:Adrenergic alpha-Agonists / Q000494:pharmacology*; D000818:Animals; D001794:Blood Pressure / Q000187:drug effects; D003655:Decerebrate State; D004305:Dose-Response Relationship, Drug; D004958:Estradiol / Q000494:pharmacology*; D004971:Estrus / Q000502:physiology*; D005260:Female; D006325:Heart Atria / Q000187:drug effects*; D006339:Heart Rate / Q000187:drug effects; D066298:In Vitro Techniques; D009469:Neuromuscular Junction / Q000187:drug effects; D010052:Ovariectomy; D010210:Papillary Muscles / Q000187:drug effects*; D051381:Rats; D017208:Rats, Wistar; D011942:Receptors, Adrenergic, alpha / Q000187:drug effects*
D000316:Adrenergic alpha-Agonists; D011942:Receptors, Adrenergic, alpha; D004958:Estradiol