Parkman H P, Pagano A P, Ryan J P
Department of Medicine, Temple University School of Medicine, Philadelphia, Pennsylvania, USA.
Gastroenterology. 1996 Sep;111(3):682-90. doi: 10.1053/gast.1996.v111.pm8780573.
BACKGROUND & AIMS: Erythromycin's effect in accelerating gastric emptying is attributed primarily to increased antral contractility. The aim of this study was to characterize erythromycin's effect on pyloric muscle.
Rabbit pyloric muscle strips were studied in vitro.
Pyloric muscle strips developed spontaneous phasic contractions with a frequency of 1.9 +/- 0.1 contractions per minute. Erythromycin and motilin had dose-dependent inhibitory effects on pyloric muscle. At the maximal effective dose (50 mumol/L), erythromycin caused cessation of spontaneous contractions for 1.8 +/- 0.2 minutes, decreasing the initial 2-minute motility index to 35% +/- 9% (P < 0.01) of basal. In the presence of tetrodotoxin, both erythromycin and motilin increased pyloric contractility. Motilin tachyphylaxis both in the presence or absence of tetrodotoxin abolished the effects of erythromycin. The inhibitory effect of erythromycin was decreased by NG-nitro-L-arginine methyl ester and the vasoactive intestinal peptide antagonist [4-Chloro-D-Phe6, Leu17]vasoactive intestinal peptide.
These studies suggest that motilin receptors are present on both pyloric muscle and inhibitory neurons to pyloric muscle, that the primary effect of erythromycin on the pylorus is mediated by activating motilin receptors on inhibitory motor neurons, and that both nitric oxide and vasoactive intestinal peptide may mediate the inhibitory effect of erythromycin.
红霉素加速胃排空的作用主要归因于胃窦收缩力增强。本研究旨在描述红霉素对幽门肌的作用。
对兔幽门肌条进行体外研究。
幽门肌条出现自发性阶段性收缩，频率为每分钟1.9±0.1次收缩。红霉素和胃动素对幽门肌有剂量依赖性抑制作用。在最大有效剂量（50μmol/L）时，红霉素使自发性收缩停止1.8±0.2分钟，将最初2分钟的运动指数降至基础值的35%±9%（P<0.01）。在存在河豚毒素的情况下，红霉素和胃动素均增加幽门收缩力。无论有无河豚毒素，胃动素快速适应性均消除了红霉素的作用。NG-硝基-L-精氨酸甲酯和血管活性肠肽拮抗剂[4-氯-D-苯丙氨酸6，亮氨酸17]血管活性肠肽可降低红霉素的抑制作用。
这些研究表明，胃动素受体存在于幽门肌和支配幽门肌的抑制性神经元上，红霉素对幽门的主要作用是通过激活抑制性运动神经元上的胃动素受体介导的，一氧化氮和血管活性肠肽可能介导红霉素的抑制作用。
