Alpha1L-adrenoceptors mediate contractions of the isolated mouse prostate.
The subtype of alpha1-adrenoceptor mediating noradrenaline-induced contractile responses in isolated mouse prostate glands was investigated. Adrenoceptor agonists were able to produce concentration-dependent contractions with the following rank order of potency: adrenaline > or = noradrenaline > or = clonidine = phenylephrine > dopamine > or = isoprenaline. Concentration-response curves to noradrenaline of the prostatic smooth muscle were antagonised by prazosin, N-[2-(2-cyclopropylmethoxyphenoxy)ethyl]-5-chloro-alpha, alpha-dimethyl-1H-indole-3-ethanamine (RS-17053), 2-(2,6-dimethoxyphenoxyethyl)aminomethyl-1,4-benzodioxane (WB 4101), tamsulosin and yohimbine with mean antagonist affinity estimates (pA2 or apparent pKB) of 8.12+/-0.10, 6.56+/-0.11, 8.38+/-0.06, 10.14+/-0.19 and 7.38+/-1.36 respectively. Propranolol (1 microM) had no antagonist activity (P = 0.994, n = 6). Yohimbine (0.01, 0.1, 1 microM) had no antagonist activity in the presence of prazosin (0.1 microM) (P > or = 0.059). The results obtained indicate that alpha1-adrenoceptors mediate the contractile response in isolated preparations of the mouse prostate. Furthermore, the particular subtype of alpha1-adrenoceptor mediating the response to exogenously administered noradrenaline corresponds to the alpha1L-subtype, the same subtype as that which has been shown to mediate noradrenaline-induced contractile activity in the human prostate.
Gray
Katherine T
KT
Prostate Research Co-operative, Victorian College of Pharmacy, Monash University, 381 Royal Parade, Parkville, Victoria, 3052, Australia.
Ventura
Sabatino
S
D058646:Adrenergic alpha-1 Receptor Agonists; D058668:Adrenergic alpha-1 Receptor Antagonists; D000316:Adrenergic alpha-Agonists / Q000494:pharmacology; D000317:Adrenergic alpha-Antagonists / Q000494:pharmacology; D000318:Adrenergic beta-Agonists / Q000494:pharmacology; D000704:Analysis of Variance; D000818:Animals; D003000:Clonidine / Q000494:pharmacology; D004146:Dioxanes / Q000494:pharmacology; D004298:Dopamine / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D004837:Epinephrine / Q000494:pharmacology; D066298:In Vitro Techniques; D007211:Indoles / Q000494:pharmacology; D007545:Isoproterenol / Q000494:pharmacology; D008297:Male; D051379:Mice; D009119:Muscle Contraction / Q000187:drug effects / Q000502:physiology*; D009638:Norepinephrine / Q000494:pharmacology; D010656:Phenylephrine / Q000494:pharmacology; D011224:Prazosin / Q000494:pharmacology; D011467:Prostate / Q000187:drug effects / Q000502:physiology*; D018340:Receptors, Adrenergic, alpha-1 / Q000502:physiology*; D015016:Yohimbine / Q000494:pharmacology
D058646:Adrenergic alpha-1 Receptor Agonists; D058668:Adrenergic alpha-1 Receptor Antagonists; D000316:Adrenergic alpha-Agonists; D000317:Adrenergic alpha-Antagonists; D000318:Adrenergic beta-Agonists; D004146:Dioxanes; D007211:Indoles; C099495:RS 17053; D018340:Receptors, Adrenergic, alpha-1; D010656:Phenylephrine; D015016:Yohimbine; C010654:(2-(2',6'-dimethoxy)phenoxyethylamino)methylbenzo-1,4-dioxane; D007545:Isoproterenol; D003000:Clonidine; D004298:Dopamine; D009638:Norepinephrine; D011224:Prazosin; D004837:Epinephrine