Influence of angiotensin II on the alpha-adrenoceptors involved in mediating the response to sympathetic nerve stimulation in the rabbit isolated distal saphenous artery.
Under normal experimental conditions, sympathetic nerve-mediated responses to electrical field stimulation in the isolated distal saphenous artery of the rabbit are sensitive to prazosin (0.1 microM) and so, by definition, are mediated by alpha 1-adrenoceptors. In the presence of angiotensin II (A II, 0.05 microM) however, a component of the response to nerve stimulation became resistant to prazosin. This 'uncovered' response was virtually abolished by the selective alpha 2-adrenoceptor antagonist rauwolscine (1 microM), a concentration that in the absence of A II had enhanced nerve-mediated responses. Exposure to A II therefore, allows the clear demonstration of a role for postjunctional alpha 2-adrenoceptors in mediating the contractile response to sympathetic nerve stimulation in this arterial preparation.
Dunn
W R
WR
Autonomic Physiology Unit, University of Glasgow.
McGrath
J C
JC
Wilson
V G
VG
D000804:Angiotensin II / Q000494:pharmacology*; D000818:Animals; D004558:Electric Stimulation; D066298:In Vitro Techniques; D008297:Male; D009119:Muscle Contraction / Q000187:drug effects; D009131:Muscle, Smooth, Vascular / Q000187:drug effects / Q000294:innervation*; D009638:Norepinephrine / Q000494:pharmacology; D011224:Prazosin / Q000494:pharmacology; D011817:Rabbits; D011942:Receptors, Adrenergic, alpha / Q000187:drug effects*; D013564:Sympathetic Nervous System / Q000187:drug effects* / Q000502:physiology; D015016:Yohimbine / Q000494:pharmacology
D011942:Receptors, Adrenergic, alpha; D000804:Angiotensin II; D015016:Yohimbine; D009638:Norepinephrine; D011224:Prazosin