Fox-Threlkeld J E, Manaka H, Manaka Y, Cipris S, Woskowska Z, Daniel E E
Department of Biomedical Sciences, Faculty of Health Sciences, McMaster University, Hamilton, Ontario, Canada.
Peptides. 1991 Sep-Oct;12(5):1047-50. doi: 10.1016/0196-9781(91)90058-w.
In the isolated perfused canine ileal segment, exogenous motilin infused for 9 min, at concentrations from 10(-10) M and 10(-8) M, increased circular muscle motility concomitant with inhibiting tonic VIP release, maximum at 10(-8) M. Both effects increased with increasing motilin concentrations. Atropine 10(-7) M pretreatment did not alter these responses. Naloxone 10(-7) M pretreatment eliminated both the increase in motor activity and the inhibition of VIP levels. Thus the nonmuscarinic neural pathway responsible for motor activation by motilin probably involves the stimulation of release of opiates, which in turn inhibit the release of VIP. Reduction of tonic inhibition of the muscle by continuous VIP release may in part account for increases in motor activity induced by motilin.
在离体灌注的犬回肠段中，以10⁻¹⁰ M至10⁻⁸ M的浓度注入外源性胃动素9分钟，可增加环行肌运动，同时抑制持续性血管活性肠肽（VIP）释放，在10⁻⁸ M时作用最强。两种效应均随胃动素浓度增加而增强。10⁻⁷ M阿托品预处理并未改变这些反应。10⁻⁷ M纳洛酮预处理消除了运动活性增加和VIP水平抑制这两种效应。因此，胃动素激活运动的非毒蕈碱神经通路可能涉及阿片类物质释放的刺激，而阿片类物质反过来又抑制VIP的释放。持续释放的VIP对肌肉的紧张性抑制作用的减弱可能部分解释了胃动素诱导的运动活性增加。
