Evidence for functional alpha-adrenoceptors in rabbit basilar arteries.
The contractile response of rabbit basilar arteries to 1-norepinephrine was studied both in the absence and in the presence of prazosin (10 nM and 1 microM). Prazosin produced a parallel shift to the right of the norepinephrine, but not the histamine, dose-response curves indicating the presence of prazosin-sensitive alpha-adrenoceptors in this vessel. The alpha-adrenoceptor-mediated contractile responses to norepinephrine in rabbit basilar arteries were much more sensitive to the deleterious effects of storage (for 18 h at 4 degrees C) than those to histamine. It is suggested that the low number of alpha-adrenoceptors in the rabbit basilar artery combined with their low sensitivity to alpha-adrenoceptor agonists, and detrimental effects associated with tissue storage may explain some inconsistent reports in the literature regarding the presence of functional alpha-adrenoceptors in rabbit basilar arteries, particularly ligand binding studies.
D000109:Acetylcholine / Q000037:antagonists & inhibitors; D000818:Animals; D001285:Atropine / Q000494:pharmacology; D001488:Basilar Artery / Q000187:drug effects / Q000294:innervation*; D003080:Cold Temperature; D006632:Histamine / Q000494:pharmacology; D066298:In Vitro Techniques; D008297:Male; D009638:Norepinephrine / Q000037:antagonists & inhibitors / Q000494:pharmacology; D011224:Prazosin / Q000494:pharmacology; D011817:Rabbits; D011942:Receptors, Adrenergic, alpha / Q000502:physiology*; D011976:Receptors, Muscarinic / Q000502:physiology; D013997:Time Factors; D014655:Vascular Resistance / Q000187:drug effects; D014661:Vasoconstriction / Q000187:drug effects
D011942:Receptors, Adrenergic, alpha; D011976:Receptors, Muscarinic; D001285:Atropine; D006632:Histamine; D000109:Acetylcholine; D009638:Norepinephrine; D011224:Prazosin