Analysis of alpha1-adrenoceptors in rabbit lower urinary tract and mesenteric artery.
In this study, we have investigated the effects of a series of alpha1-adrenoceptor antagonists on the phenylephrine-mediated contractions of rabbit isolated prostate, urethra, trigone and mesenteric artery. With the exception of RS-17053 (N-[2-(2-cyclopropylmethoxyphenoxy)ethyl]-5-chloro-alpha,alpha-dim ethyl-1 H-indole-3-ethanamine hydrochloride), the antagonists displayed the lowest potency in the urethra. Catecholamine uptake1 and uptake2 appeared not to be the cause for the low pK(B)/pA2 values obtained in the urethra because cocaine and corticosterone had no effect on the potency of phenylephrine in this tissue. The low potencies displayed by prazosin. RS-17053 and HV723 (alpha-ethyl-3,4,5-trimethoxy-alpha-(3-((2-(2-methoxyphenoxy)ethyl)amino )propyl)benzene-acetonitrile fumarate) suggest that the functional receptors in all four tissues belong to the alpha(1L)-adrenoceptor class. Whether or not the significant between-tissue differences in antagonist potencies are due to heterogeneity of this receptor class remains to be elucidated.
Van der Graaf
P H
PH
Synthélabo Recherche (L.E.R.S.), Department of Internal Medicine, Rueil Malmaison, France.
Deplanne
V
V
Duquenne
C
C
Angel
I
I
D000317:Adrenergic alpha-Antagonists / Q000494:pharmacology; D000818:Animals; D066298:In Vitro Techniques; D008297:Male; D008638:Mesenteric Arteries / Q000187:drug effects* / Q000502:physiology; D010656:Phenylephrine / Q000494:pharmacology; D010879:Piperazines / Q000494:pharmacology; D011467:Prostate / Q000187:drug effects / Q000502:physiology; D011817:Rabbits; D018340:Receptors, Adrenergic, alpha-1 / Q000145:classification / Q000502:physiology*; D014521:Urethra / Q000187:drug effects / Q000502:physiology; D014551:Urinary Tract / Q000187:drug effects*; D014553:Urinary Tract Physiological Phenomena
D000317:Adrenergic alpha-Antagonists; D010879:Piperazines; D018340:Receptors, Adrenergic, alpha-1; D010656:Phenylephrine; C053428:BMY 7378