β-아드레날린성 수용체 아형에 대한 효현제 및 길항제가 토끼 정낭의 수축 및 이완 반응에 미치는 영향

Abstract

Purpose: This study was aimed at investigating the role of β-adrenoceptor subtypes in mediating the relaxation and contraction of seminal vesicles in rabbits. Materials and Methods: Relaxation or contractile responses of epithelium- removed muscle strips of a rabbit seminal vesicle, which were precontracted with 10-5M norepinephrine, to selective β subtypes-adrenoceptor agonists were observed in an organ bath. The contractile responses induced by isoproterenol were also observed after application of selective antagonists. Results: Isoproterenol showed a concentration-dependent contractile response, but the contractility was weaker than those with phenylephrine and norepinephrine. The β selective-agonists(xamoterol for β1, clenbuterol for β2 and BRL37344 for β3) alone evoked neither contraction nor relaxation. However, the β1- and β3-agonists inhibited the contraction of the precontracted strips with 10-5M norepinephrine, while the β2-agonist enhanced the contraction. The pretreatment with a β2-antagonist(ICI118551) reduced the tension of the strips developed by 10-4M isoproterenol, but the β1-(atenolol) and β3-(SR59230A) antagonists showed no changes in the response. Conclusions: β1- and β3-adrenoceptors seem to mediate the relaxation of the seminal vesicle, while the β2-adrenoceptor may have a supplementary role in contraction. (Korean J Urol 2004;45:726-731)