目的:探讨生长激素促分泌素受体及其激动剂GHRP-6对小鼠结肠动力的影响及机制.方法:小鼠随机分组后,分别注射生理盐水、GHRP-6 (20、50、100、200 μg/kg),用炭末推进实验的方法研究GHRP-6对小鼠结肠推进的影响.小鼠近端结肠环形平滑肌条安置在恒温灌流肌槽中,并用SMUP-E生物信号处理系统记录肌条的自发收缩活动,观察不同浓度的GHRP-6(0.01、0.1、1和10 μ mol/L)对肌条自发收缩幅度的影响,以及神经阻断剂TTX和GHS-R阻断剂D-lys3-GHRP-6孵育肌条情况下,GHRP-6对肌条自发收缩幅度的影响.结果:GHRP-6注射剂量在50、100、200 μ g/kg时均能显著提高小鼠的结肠推进(P＜0.05).GHRP-6浓度在0.1、1和10 μ mol/L时均能显著增加小鼠近端结肠环形平滑肌条的自发收缩幅度(P＜0.05),在TTX和D-lys3-GHRP-6孵育肌条下,Ghrelin不能增加小鼠结肠环形平滑肌条的自发收缩幅度.结论:GHRP-6可以显著增加小鼠的结肠推进,其机制可能是通过肠肌间神经丛的的GHS-R受体而起作用.%Objective: To investigate the effects and mechanisms of growth hormone secreta-gogue receptor and its agonist GHRP-6 on colonic motility in mices. Methods: In vivo, the dose depend effects of GHRP-6 (20, 50, 100, 200 μg/kg) on colonic transit were measured by charcoal suspension pushing test. In vitro, the effects of GHRP-6 (0.01, 0.1, 1 and 10 μmol/L) on sponta-' neous contraction of proximal colonic isolated circular muscle strips were studied in the presence of TTX or D-lys3-GHRP-6 or not. Results: GHRP-6 (50, 100, 200 μg/kg) significantly accelerated colonic transit (P<0.05). GHRP-6 (0.1, 1 and 10 μmol/L)significantly increased the spontaneous contraction of the proximal colonic circular muscle strips (P<0.05), TTX or D-lys3-GHRP-6 can block the reaction. Conclusion: GHRP-6 accelerate colonic transit perhaps by activating GHS-R in the enteric nervous system.
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