Effect of bunazosin, alpha 1-adrenoceptor blocker, on multidirectional contractile response and localization of bunazosin binding sites in human hypertrophied prostate.
1. Effects of bunazosin, an alpha 1-adrenoceptor blocker, on the contraction induced by norepinephrine in human hypertrophied prostate were examined in vitro. 2. Prostatic specimens showed maximum contraction at 10(-4) M norepinephrine in longitudinal and circumferential directions to the urethra. 3. Bunazosin (10(-7) M) blocked norepinephrine-induced contraction with a parallel shift of the dose-response curve in both directions (pA2: 8.76 +/- 0.15; pA2: 8.90 +/- 0.08, respectively). 4. Serial sections of prostates were also evaluated by autoradiography. The binding sites were diffusely distributed in the interstitium. 5. We concluded that bunazosin affects multidirectional contraction in prostates.
Moriyama
N
N
Department of Urology, Faculty of Medicine, University of Tokyo, Japan.
Orikasa
E
E
Nakamura
T
T
Kurimoto
S
S
Ishida
Y
Y
Kawabe
K
K
D058668:Adrenergic alpha-1 Receptor Antagonists; D000317:Adrenergic alpha-Antagonists / Q000494:pharmacology*; D000368:Aged; D000369:Aged, 80 and over; D001345:Autoradiography; D001665:Binding Sites / Q000187:drug effects; D006801:Humans; D066298:In Vitro Techniques; D008297:Male; D008875:Middle Aged; D009119:Muscle Contraction / Q000187:drug effects; D009130:Muscle, Smooth / Q000187:drug effects*; D009638:Norepinephrine / Q000494:pharmacology; D011467:Prostate / Q000187:drug effects* / Q000378:metabolism; D011470:Prostatic Hyperplasia / Q000378:metabolism* / Q000503:physiopathology; D011799:Quinazolines / Q000494:pharmacology*; D018340:Receptors, Adrenergic, alpha-1 / Q000378:metabolism
D058668:Adrenergic alpha-1 Receptor Antagonists; D000317:Adrenergic alpha-Antagonists; D011799:Quinazolines; D018340:Receptors, Adrenergic, alpha-1; C018176:bunazosin; D009638:Norepinephrine