Influences of androgen for detrusor function

Research Project

Project/Area Number	12671549
Research Category	Grant-in-Aid for Scientific Research (C)
Allocation Type	Single-year Grants
Section	一般
Research Field	Urology
Research Institution	Fukushima Medical University
Principal Investigator	YOKOTA Takashi Fukushima Medical University, School of Medicine, Associate Professor, 医学部・泌尿器科, 助教授 (20240939)
Project Period (FY)	2000 – 2002
Project Status	Completed (Fiscal Year 2002)
Budget Amount *help	¥3,500,000 (Direct Cost: ¥3,500,000) Fiscal Year 2002: ¥500,000 (Direct Cost: ¥500,000) Fiscal Year 2001: ¥1,200,000 (Direct Cost: ¥1,200,000) Fiscal Year 2000: ¥1,800,000 (Direct Cost: ¥1,800,000)
Keywords	Androgen / male rat / Detrusor function / Benign prostatic hyperplasia / Detrusor contractile hyperplasia / Castration / 排尿筋機能障害 / 性ホルモン / 去勢ラット / ムスカリン受容体 / 排尿筋収縮力 / 等尺性収縮実験 / 収縮速度 / PFS / ラット / 前立腺腫大
Research Abstract	Male Sprague-Dawley rats, 16 weeks old, were used for this study. These rats are divided into two groups both castration and control. 4 weeks after castration, using isolated detrusor strips which were taken from these both bladders and mounted in an organ bath, in vitro contraction studies were performed to evaluate the contractile responses to agonist, the responses to electrical field stimulation(EFS) and the force-velocity relation to determine power of detrusor muscle. The dose-response curves for carbachol and α, β -methylene ATP did not differ from both detrusor strips. Thus, function of muscarinc receptor and purinoceptor were not changed after castration. EFS (15 voltage, 0.5msec duration) produced frequency -dependent contraction. At lower frequency(below 10 Hz), there seems to be slightly weak responses in castration group. However, at high frequency, the contractile responses were not altered. These results may suggest that castration influences function of nerve and/or secretion of neurotransmitters such as purinergic neuron. Power consists of force(F) and speed contraction(V) of muscle. Thus, we carried out an isotonic contraction study to measure velocity of detrusor muscle contraction. When EFS (50Hz) is applied, detrusor strip shortens against various loads. This velocity of shortening is calculated from a gradient of this shortening curve. A force-velocity curve, of castration group is situated under the curve of control group. Average power per unit tissue weight were 6.57 × 10^<-3>watt/g on control group and 3.18 × 10^<-3>watt/g on castration group. This study suggests that ancirogen influences power of detrusor muscle, directly. Bladder muscle could be a possible target of androgen.