肛直肠抑制反射时门静脉血中P物质变化

目的探讨肛直肠抑制反射（RAIR）时门静脉血中P物质（SP）的变化规律及外源性内脏神经对其变化的影响。方法将实验大白鼠分为7组，其中6组先按去与不去直肠肛管外源性内脏神经支配而分为不去神经和去神经两大组，每组中又按Foley导管上气囊置入直肠腔中的位置分为2、4、6cm组；同时再设1个对照组，将Foley导管置入直肠腔中，但不注水扩张球囊。检测并比较在直肠腔内刺激后，各组门静脉血中的SP值及变化情况。结果去神经组中2、4cm组与不去神经组之间及对照组之间，门静脉血中SP值变化比较，P〉0．05，差异无统计学意义。不去神经组中的6cm组与对照组及去神经组中2cm和4cm组之间SP值比较，P〈0．01，差异有统计学意义；去神经组和不去神经组中的6cm组之间SP值比较，P〈0．01，差异有统计学意义。结论直肠腔内上部的刺激不引出RAIR可能与该部位的刺激使内括约肌兴奋性递质（SP）的释放有关；外源性内脏神经对RAIR中门静脉血的SP变化有调控作用。

Change of substance P in portal vein during rectoanal inhibitory reflex

OBJECTIVE: To investigate the change pattern of substance P (SP) in the portal vein during the rectoanal inhibitory reflex (RAIR), and its physiologic significance; the influence of external splanchnic nerve of rectum and anal to the RAIR. METHODS: The rats were divided into seven groups, among them there were six groups, which were first divided into two big groups according to whether the external splanchnic nerve to the rectum and anal were cut off, one is no cut-off external splanchnic nerve group, the other is cut-off external splanchnic nerve group. Each group were further divided, according to the distance of the balloon-sac on Foley's tube in the rectum away from anal verge, into 2, 4, 6 centimeter groups; A control group with Foley's tube put into the rectum, but the balloon-sac on Foley's tube did not pumped up with water. Measure and compare the value and change of SP in the portal vein during the RAIR. RESULTS: The comparison of SP in portal vein, among the 2, 4 centimeter groups with cut-off external splanchnic nerve, all groups with intact external splanchnic nerve supply and control group, had no statistic difference (P>0.05). The comparison between the 6 centimeter group with intact external splanchnic nerve group and the 2, 4 centimeter groups with cut-off external splanchnic nerve, P<0.01, the statistic difference was significant. The comparison between 6 centimeter group of intact and cut-off external splanchnic nerve, P<0.01, the difference was significant. CONCLUSION: The reason for the stimulation on upper rectum dose not induce the RAIR is related with this stimulation result in the release of SP, the exciting mediator to internal sphincter. The external splanchnic nerve supply of rectum and anal canal have influence on the change of SP of the portal vein during RAIR.