Kontani H, Inoue T, Sakai T
Department of Pharmacology, Hokuriku University, School of Pharmacy, Kanazawa, Japan.
Jpn J Pharmacol. 1990 Jan;52(1):59-67. doi: 10.1254/jjp.52.59.
We studied the effects of apomorphine (AM) on bladder motility in anesthetized rats in which Tyrode's solution was continuously infused into the bladder at a constant rate, including an almost constant rate of bladder contraction accompanying micturition. AM at a dose of 1 mg/kg, i.v., caused a hyperactive bladder response, during which micturition disappeared. AM (12.5 micrograms for intracerebroventricular (i.c.v.) injection or 50 micrograms for intrathecal (i.t.) injection also caused a hyperactive response in about half of the rats. Supersensitization to AM appeared in reserpine-treated rats (2.5 mg/kg, i.p., 48 and 24 hr before the experiment). Haloperidol (1 mg/kg, i.v.) or SCH 23390 (5 mg/kg, i.v.) completely suppressed the hyperactive bladder response induced by AM (5 mg/kg, i.v.), and then the bladder contraction accompanying micturition reappeared after administration of these drugs. Pretreatment with sulpiride (100 mg/kg, i.p.) for 60 min, which hardly affected the bladder contraction induced by infusion of Tyrode's solution, suppressed the hyperactive bladder response induced by AM. These results suggest that the hyperactive bladder response induced by i.v.-injected AM results from synchronous stimulation of the micturition reflex centers in the brain stem and sacral cord and that the hyperactive bladder response is elicited via both D1 and D2 receptors.
我们研究了阿扑吗啡（AM）对麻醉大鼠膀胱运动的影响，在这些大鼠中，以恒定速率持续向膀胱内输注台氏液，包括排尿时几乎恒定的膀胱收缩速率。静脉注射1mg/kg剂量的AM会引起膀胱反应亢进，在此期间排尿消失。脑室内（i.c.v.）注射12.5μg或鞘内（i.t.）注射50μg的AM也会在约一半的大鼠中引起反应亢进。在利血平处理的大鼠（实验前48小时和24小时腹腔注射2.5mg/kg）中出现了对AM的超敏反应。氟哌啶醇（静脉注射1mg/kg）或SCH 23390（静脉注射5mg/kg）完全抑制了AM（静脉注射5mg/kg）诱导的膀胱反应亢进，然后在给予这些药物后排尿时的膀胱收缩再次出现。预先用舒必利（腹腔注射100mg/kg）处理60分钟，这几乎不影响输注台氏液诱导的膀胱收缩，但抑制了AM诱导的膀胱反应亢进。这些结果表明，静脉注射AM诱导的膀胱反应亢进是由于脑干和脊髓中排尿反射中枢的同步刺激所致，并且膀胱反应亢进是通过D1和D2受体两者引发的。
