脑室内注射5-羟色胺受体激动剂对正常清醒大鼠排尿反射的影响

Effects of intracerebroventricular administration of 5-hydroxytryptamine receptor agonists on micturition reflex in normal conscious rats

目的探讨脑室内注射5-羟色胺(5-HT)受体激动剂对正常清醒大鼠排尿反射的影响。方法 SD大鼠30只随机分为5组,将PE-50聚乙烯导管分别插入大鼠膀胱顶部及右侧脑室进行膀胱测压与药物注入。在脑室内分别注入5-HT、5-HT1A受体激动剂8-OH-DPAT、5-HT2受体激动剂1-甲基-5-HT、5-HT3受体激动剂2-甲基-5-HT以及5-HT4受体激动剂RS67506,剂量分别为6、18或60nmol·kg^(-1)。记录给药前后的排尿压力、膀胱容量、排尿量以及残尿量等指数的变化。结果 6nmol·kg^(-1)剂量的5-HT、8-OH-DPAT、1-甲基-5-HT和RS67506即开始促进排尿,主要表现为大鼠膀胱容量及排尿量减少。18nmol·kg^(-1)剂量则进一步促进排尿反射,表现为大鼠排尿压力显著增加,膀胱容量及排尿量更加减少。而60nmol·kg^(-1)剂量的2-甲基-5-HT对膀胱测压参数仍然无影响。结论在正常清醒大鼠的高位中枢水平,5-HT1A、5-HT2、5-HT4受体激动剂能促进排尿反射。

AIM To investigate the effects of intracerebroventricular administration of 5-hydroxytryptamine （5-HT）receptor agonists on micturition reflex in normal conscious rats.METHODS Thirty normal SD rats were randomized into 5 groups.A PE-50 catheter was placed into the dome of the bladder to record intravesical pressure.And a cerebroventricular cannula was inserted into the right ventricle for the injection of 5- HT,8-hydroxy-N,N-dipropyl-2-aminotetralin（8-OH-DPAT,agonist at 5-HT1A receptor）,1-methyl-5-HT （agonist at 5-HT2 receptor）,2-methyl-5-HT（agonist at 5-HT3 receptor）,and 1-（4-amino-5-chloro2methoxyphenyl） -3-（1-n-butyl-4piperidinyl）-1-propanone hydrochloride（RS67506,agonist at 5-HT4 receptor）.The dosage was 6,18 or 60 nmol·kg^-1,respectively.Micturition pressure,bladder capacity, micturition volume and residual volume etc,before and after the administration were measured.RESULTS In the normal conscious rats,6 nmol·kg^-15HT,8-OH-DPAT,1-methyl-5-HT,or RS67506 injected intracerebroventricularly promoted micturition reflex with decreased bladder capacity and residual volume;18 nmol·kg^-1 promoted micturition reflex more significantly.But there was no effect on cystometric parameters in the rats injected with 2-methyl-5-HT.CONCLUSION In normal conscious rats,5-HT1A,5-HT2,5-HT4 receptor agonists can promote the micturition reflex in the level of superspinal central nervous system.