Kontani H, Kawabata Y, Koshiura R
Department of Pharmacology, Hokuriku University, School of Pharmacy, Kanazawa, Japan.
Jpn J Pharmacol. 1988 Jan;46(1):7-15. doi: 10.1254/jjp.46.7.
We studied the effects of baclofen on the bladder contraction induced by infusion of Tyrode's solution into the urinary bladder in anesthetized rats. Baclofen (5 mg/kg, i.v.) completely inhibited bladder contraction and abolished the efferent discharges recorded from the left pelvic nerve, causing the bladder pressure to rise until solution leaked from the penis. The inhibitory effect of baclofen (5 mg/kg, i.v.) could not be reversed by picrotoxin (1 mg/kg, i.v., twice with an interval of 10 min) or naloxone (1 mg/kg, i.v.). In parallel with convulsion, strychnine (1 mg/kg, i.v.) contracted the bladder which had been inhibited by baclofen and generated electrical activities consisting of efferent discharges and electromyograms. The dose of intracerebroventricularly or intrathecally injected baclofen which completely inhibited the bladder contraction was 0.1 or 10 micrograms, respectively. After the inhibition of bladder contraction by i.v. injection of baclofen, electrical stimulation of the sacral cord could contract the bladder and cause a fall in bladder pressure to around the level existing after micturition. From these results, the active site of baclofen which is related to the inhibition of bladder contraction is thought to be the micturition center in the brain stem.
我们研究了巴氯芬对麻醉大鼠膀胱内注入台氏液所诱导的膀胱收缩的影响。巴氯芬（5毫克/千克，静脉注射）完全抑制了膀胱收缩，并消除了从左侧盆神经记录到的传出放电，导致膀胱压力升高直至尿液从阴茎漏出。巴氯芬（5毫克/千克，静脉注射）的抑制作用不能被印防己毒素（1毫克/千克，静脉注射，间隔10分钟注射两次）或纳洛酮（1毫克/千克，静脉注射）逆转。与惊厥同时，士的宁（1毫克/千克，静脉注射）使已被巴氯芬抑制的膀胱收缩，并产生由传出放电和肌电图组成的电活动。脑室内或鞘内注射能完全抑制膀胱收缩的巴氯芬剂量分别为0.1或10微克。静脉注射巴氯芬抑制膀胱收缩后，电刺激骶髓可使膀胱收缩，并使膀胱压力降至排尿后存在的水平左右。从这些结果来看，巴氯芬与抑制膀胱收缩相关的作用位点被认为是脑干中的排尿中枢。
