药物对小鼠胃片GABA摄取的影响

Effects of Drugs on GABA Uptake of Stomach Slices in Mice

本文应用同位素示踪技术和离体孵育小鼠胃片的方法,探讨了与调节胃功能活动的GABA相关的药物对胃片摄取GABA的影响。实验显示,GABA-T抑制剂AOAA在低剂量时(1～5mmol·L^(-1))可抑制胃片摄取GABA(P<0.01),而高剂量时(10mmol·L^(-1))能促进GABA摄取(P<0.05)。蝇(?)醇(Muscimol),是一种GABA_A受体激动剂,0.5μg·ml^(-1)时能促进胃片摄取GABA(P<0.01)。胆碱能神经M型受体阻断剂阿托品(0.01～0.25mg·ml^(-1))能抑制胃片摄取GABA(P<0.01)。盐酸(0.01～0.05N)和胃蛋白酶(0.05～1mg·ml^(-1))二者都能促进胃片摄取GABA(P<0.05或0.01)。这些结果提示:胃的GABA摄取系统可能有一种负反馈式自身调节机制。即当GABA调节胃功能活动增强时,它会加速GABA摄取,结果是尽快地终止GABA对胃的效应;相反当GABA调节胃功能活动减弱时,可抑制GABA摄取,结果是保持GABA对胃的作用,从而维持胃功能的稳态。

The paper studies the effects of the drugs relative to GABA and the physiological functions mediated by GABA on the GABA uptake of stomach slices in mice by means of the radiotracing in vitro. The results show that AOAA, an inhibitor of GABA-T, inhibits the GABA uptake of stomach slices at lower doses(l^5mmol·L-1)(P<0. 01), but accelerates the GABA uptake at higher dose (10mmol·L-1)(P<0. 05). Muscimol(0.5μg·ml-1), an agonist of GABAA receptor, accelerates the GABA uptake of stomach slices (P<0. 01). Atropine(0. 01~0. 25mg ·ml-1),a blocker of cholinergic M receptor, inhibits the GABA uptake of stomach slices(P< 0. 01). Both HCI(0. 01~0. 05N) and pepsin (0. 05~lmg·ml-1) also accelerate the GABA uptake of stomach slices (P<0. 05 or 0. 01). According to these results, a supposition can be suggested that posssibly there is a mechanism of feedback autoreguiation of GABA uptake system in mouse stomach. When the stomach functions mediated by GABA are strengthened, the GABA uptake in stomach will be increased. But when stomach functions are weakened, the GABA uptake will be inhibited. Thereby the GABA effects and the physiolocal functions mediated by GABA in stomach are kept at normal levels.