Holzer-Petsche U, Lembeck F
Br J Pharmacol. 1984 Dec;83(4):935-41. doi: 10.1111/j.1476-5381.1984.tb16534.x.
Filling the urinary bladder via a urethral cannula and preventing its voiding in anaesthetized rats led to rhythmic contractions of the detrusor muscle, which lasted for more than 1 h. This rhythmic activity ceased about 30 min after a s.c. injection of 50 mg kg-1 capsaicin. The contractile response of the detrusor to topically applied capsaicin was lost after systemic administration of the toxin, whereas no change in the sensitivity to acetylcholine was observed. Urinary bladders of normal rats had a capacity of about 1 ml. Bladders of rats treated with capsaicin as neonates held a volume of more than 5 ml without contracting. Such bladders were insensitive to topically applied capsaicin but they contracted to acetylcholine as strongly as the bladders of control rats. During an observation period of 3 days control rats gained weight at night and lost weight by day. Rats treated with capsaicin as neonates showed little fluctuation in body weight. Such rats hardly excreted any urine by day although at night they excreted as much as controls. A water load of 5 ml 100 g-1 was excreted by control rats within 3 h. Rats treated with capsaicin as neonates excreted only half as much. In addition, 50% of the water load was excreted far later by capsaicin treated rats than by controls. Few changes were observed in rats treated with capsaicin as adults. It is concluded that all primary afferent fibres mediating the sensation of a full bladder are capsaicin-sensitive. An additional effect of capsaicin on renal mechanisms cannot be excluded.
通过尿道插管向麻醉大鼠的膀胱内注水并阻止其排尿，可导致逼尿肌出现节律性收缩，这种收缩可持续1小时以上。在皮下注射50mg/kg辣椒素后约30分钟，这种节律性活动停止。全身给予毒素后，逼尿肌对局部应用辣椒素的收缩反应消失，而对乙酰胆碱的敏感性未观察到变化。正常大鼠的膀胱容量约为1ml。新生期用辣椒素处理的大鼠膀胱可容纳超过5ml的尿液而不收缩。这种膀胱对局部应用辣椒素不敏感，但对乙酰胆碱的收缩反应与对照大鼠的膀胱一样强烈。在3天的观察期内，对照大鼠夜间体重增加，白天体重减轻。新生期用辣椒素处理的大鼠体重波动很小。这类大鼠白天几乎不排尿，尽管夜间排尿量与对照大鼠相同。对照大鼠在3小时内排出了5ml/100g体重的水负荷。新生期用辣椒素处理的大鼠排出量仅为对照大鼠的一半。此外，辣椒素处理的大鼠排出50%水负荷的时间比对照大鼠晚得多。成年期用辣椒素处理的大鼠未观察到明显变化。结论是，所有介导膀胱充盈感觉的初级传入纤维对辣椒素敏感。不能排除辣椒素对肾脏机制的额外作用。
