【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(1～16Hz)电刺激胃底部肌间神经,平滑肌条呈现开电刺激(on-re-sponse)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。更多还原

【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.更多还原