title: Dissociation of presynaptic alpha 2-adrenoceptors following prazosin administration: presynaptic effect of prazosin.
abstract: Evidence has been obtained that prazosin possesses a presynaptic alpha 2-adrenoceptor blocking action in the rat was deferens preparation stimulated at 1 Hz. In the presence of prazosin yohimbine failed to affect the presynaptic alpha 2-adrenoceptor stimulatory effect of 1-noradrenaline while the effect of xylazine was almost completely abolished. It is therefore suggested that there are two kinetically different prejunctional alpha 2-adrenoceptor sites.
mesh_terms: D000818:Animals; D066298:In Vitro Techniques; D008297:Male; D009119:Muscle Contraction / Q000187:drug effects; D009130:Muscle, Smooth / Q000187:drug effects; D009638:Norepinephrine / Q000494:pharmacology; D011224:Prazosin / Q000494:pharmacology*; D011433:Propranolol / Q000494:pharmacology; D011799:Quinazolines / Q000494:pharmacology*; D051381:Rats; D011942:Receptors, Adrenergic, alpha / Q000187:drug effects*; D013569:Synapses; D014649:Vas Deferens / Q000187:drug effects; D014991:Xylazine / Q000494:pharmacology; D015016:Yohimbine / Q000494:pharmacology
chemical_list: D011799:Quinazolines; D011942:Receptors, Adrenergic, alpha; D014991:Xylazine; D015016:Yohimbine; D011433:Propranolol; D009638:Norepinephrine; D011224:Prazosin