摘要: |
目的:探讨并比较Ghrelin及其拟似剂生长激素释放肽6(GHRP6)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GHRP6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(LNNA)、一氧化氮前体L精氨酸(LAA)对Ghrelin和GHRP6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(onresponse)的舒张波和随后出现的断电刺激(offresponse)收缩波,其中产生的开电刺激舒张效应可被LNNA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GHRP6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GHRP6。LNNA可显著增强Ghrelin和GHRP6的促平滑肌收缩效应,但LAA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GHRP6均可使该收缩作用增强。结论:Ghrelin和GHRP6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). |
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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 (GHRP6) 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 GHRP6 on the contractility of stomach smooth muscle. The influences of NnitroLarginine (LNNA) and LArginine (LAA) on the effect of Ghrelin and GHRP6 were studied to disclose the mechanism of the effects of Ghrelin and GHRP6. Results: The circular muscle tissues of the gastric fundus generated onrelaxations and offcontractions when stimulating myenteric plexuses with 116 Hz electrical field; the onresponses induced relaxation could be reduced by LNNA and the offcontractions induced contraction could be blocked by atropine and guanethidine. In fundic strips, ghrelin and GHRP6 could decrease the onresponse induced relaxation and increase offresponse induced contraction of the muscle, with the effect of Ghrelin obviously stronger than that of GHRP6.LNNA could increase the effects of Ghrelin and GHRP6induced muscle contraction, and LAA could decrease their effects. In the antral strips, electrical field stimulation of myenteric plexuses led to disappearance of relaxation wave, only leaving offcontractions. Both ghrelin and GHRP6 could increase that contraction.Conclusion: Both ghrelin and GHRP6 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 |