Volant K, Grishina O, Descroix-Vagne M, Pansu D
Unité INSERM U 45: Systeme neuro-endocrine et épithélium intestinal normal et néoplasique, Hôpital Edouard Herriot, Lyon, France.
Eur J Pharmacol. 1997 Jun 11;328(2-3):217-27. doi: 10.1016/s0014-2999(97)83048-8.
The heat-stable enterotoxin of Escherichia coli binds to an intestinal receptor, guanylyl cyclase-C, and produces cGMP to induce diarrhea. Guanylin is an endogenous ligand of this receptor. In the present in vivo study, the intestinal water and ion secretion induced by mucosal application of 2 nmol/ml guanylin or 5 or 10 units/ml heat-stable enterotoxin into closed loops was compared in the rat. The characteristics of secretion induced by cAMP following intravenous perfusion of 1.2 nmol/100 g per h vasoactive intestinal peptide were compared to those induced by cGMP. Unidirectional Na+ and Cl- fluxes were estimated by addition of 22Na into the loop and i.v. injection of 36Cl. Guanylin induced less water and ion secretion than that produced by heat-stable enterotoxin in the colon, confirming the results of in vitro studies, and also in duodenum and ileum. The cAMP- or cGMP-mediated response had a similar pattern, i.e., an inhibition of Na+ absorption and an increase in anion secretion.
大肠杆菌的热稳定肠毒素与一种肠道受体——鸟苷酸环化酶-C结合，并产生环鸟苷酸（cGMP）以诱导腹泻。鸟苷蛋白是该受体的内源性配体。在本体内研究中，比较了在大鼠封闭肠袢中黏膜应用2 nmol/ml鸟苷蛋白或5或10单位/ml热稳定肠毒素所诱导的肠道水和离子分泌情况。将每小时静脉灌注1.2 nmol/100 g血管活性肠肽后由环磷酸腺苷（cAMP）诱导的分泌特征与由cGMP诱导的分泌特征进行了比较。通过向肠袢中添加22Na和静脉注射36Cl来估算单向钠和氯通量。鸟苷蛋白在结肠中诱导的水和离子分泌比热稳定肠毒素少，这证实了体外研究结果，在十二指肠和回肠中也是如此。cAMP或cGMP介导的反应具有相似模式，即抑制钠吸收并增加阴离子分泌。
