Increase in response and number of alpha-adrenoceptors of rat vas deferens on brief pretreatment with an alpha-agonist.
The contractile response of rat vas deferens to epinephrine (E) was enhanced by preincubation with E. After pretreatment with E, there was no significant change in the ED50 of E but there was a significant increase in the maximum response (39%). There was no change in the cholinergic response after the pretreatment. alpha-Adrenoceptors in control and E-treated tissues were assessed by measuring [3H]WB-4101 binding. Treatment with E resulted in a 27% increase in the number of alpha-adrenoceptors, but no change in muscarinic acetylcholine receptors measured with [3H]quinuclidinyl benzilate. These results are discussed in relation to the response of alpha-adrenoceptors to the agonist.
D000316:Adrenergic alpha-Agonists / Q000494:pharmacology*; D000818:Animals; D001665:Binding Sites; D004837:Epinephrine / Q000494:pharmacology; D066298:In Vitro Techniques; D008297:Male; D009119:Muscle Contraction / Q000187:drug effects; D051381:Rats; D011941:Receptors, Adrenergic / Q000502:physiology*; D011942:Receptors, Adrenergic, alpha / Q000032:analysis / Q000187:drug effects / Q000502:physiology*; D013696:Temperature; D014649:Vas Deferens / Q000032:analysis / Q000502:physiology
D000316:Adrenergic alpha-Agonists; D011941:Receptors, Adrenergic; D011942:Receptors, Adrenergic, alpha; D004837:Epinephrine