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Ghrelin对豚鼠胃平滑肌收缩的影响及机制
陶园，徐珞*
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(青岛大学医学院病理生理学教研室, 青岛 266021)

摘要:

目的:探讨并比较Ghrelin及其拟似剂生长激素释放肽6(GHRP6)对豚鼠胃平滑肌舒缩活动的影响及机制。方法:采用电场刺激豚鼠胃底和胃窦部肌间神经方法，观察Ghrelin和GHRP6对胃平滑肌舒缩活动的影响，并通过观察一氧化氮合酶(NOS)抑制剂Nω硝基L精氨酸(LNNA)、一氧化氮前体L精氨酸(LAA)对Ghrelin和GHRP6调控胃平滑肌运动的影响以阐明其机制。结果:不同频率(1~16 Hz)电刺激胃底部肌间神经，平滑肌条呈现开电刺激(onresponse)的舒张波和随后出现的断电刺激(offresponse)收缩波，其中产生的开电刺激舒张效应可被LNNA消除，而断电刺激诱导的收缩效应可被阿托品和胍乙啶(NANC)阻断。在胃底部，Ghrelin和GHRP6可使开电刺激诱导的平滑肌舒张活动减弱，断电刺激诱导的肌条收缩活动增强，且Ghrelin作用明显强于GHRP6。LNNA可显著增强Ghrelin和GHRP6的促平滑肌收缩效应，但LAA可显著减弱该作用。在胃窦部，电场刺激肌间神经，舒张波消失，仅出现断电刺激的收缩波。Ghrelin和GHRP6均可使该收缩作用增强。结论:Ghrelin和GHRP6均可通过肌间神经丛促进胃底部、胃窦部平滑肌收缩，该效应可能与一氧化氮通路有关。

关键词: Ghrelin GHRP 6 一氧化氮胃肌收缩胃肌间神经

DOI：10.3724/SP.J.1008.2009.0238

投稿时间：2008-08-15修订日期：2008-09-22

基金项目:国家自然科学基金(30470642,30670780)；山东省科技攻关项目 (2008GG10002006)；山东省卫生厅项目(2007HZ026);青岛市科技局项目(05 1 JC 93).

Effect of Ghrelin on contractility of gastric smooth muscle in guinea pigs and the related mechanism

TAO Yuan, XU Luo*

(Department of Pathophysiology, Medical College of Qingdao University, Qingdao 266021, China)

Abstract:

Objective:To investigate and compare the influences of Ghrelin and growth hormone releasing peptide 6 (GHRP6) on the contractility of stomach smooth muscle in guinea pigs, and to study the related mechanism.Methods: The myenteric plexuses of gastric fundus and antrium in guinea pigs were stimulated with electrical field stimulation (EFS) to observe the influence of Ghrelin and GHRP6 on the contractility of stomach smooth muscle. The influences of NnitroLarginine (LNNA) and LArginine (LAA) on the effect of Ghrelin and GHRP6 were studied to disclose the mechanism of the effects of Ghrelin and GHRP6. Results: The circular muscle tissues of the gastric fundus generated onrelaxations and offcontractions when stimulating myenteric plexuses with 116 Hz electrical field; the onresponses induced relaxation could be reduced by LNNA and the offcontractions induced contraction could be blocked by atropine and guanethidine. In fundic strips, ghrelin and GHRP6 could decrease the onresponse induced relaxation and increase offresponse induced contraction of the muscle, with the effect of Ghrelin obviously stronger than that of GHRP6.LNNA could increase the effects of Ghrelin and GHRP6induced muscle contraction, and LAA could decrease their effects. In the antral strips, electrical field stimulation of myenteric plexuses led to disappearance of relaxation wave, only leaving offcontractions. Both ghrelin and GHRP6 could increase that contraction.Conclusion: Both ghrelin and GHRP6 can promote the contractility of stomach smooth muscle in guinea pigs through stimulating myenteric plexuses of gastric fundus and antrium, which might be related to the NO pathway.

Key words: Ghrelin growth hormone releasing peptide 6 nitric oxide stomach gastric myenteric plexus