Merlo A, Cohen S
Department of Medicine, Temple University School of Medicine, Philadelphia, Pennsylvania 19140.
Am J Physiol. 1989 May;256(5 Pt 1):G862-7. doi: 10.1152/ajpgi.1989.256.5.G862.
Mechanical properties and neuropeptide responses were compared for feline pyloric and gastric muscle under isometric conditions in vitro. Total tension in antral circular muscle (0.699 +/- 0.003 kg/cm2) was less than in corpus circular (1.597 +/- 0.007 kg/cm2) or longitudinal muscle from the lesser and greater curvatures (1.256 +/- 0.009 and 1.253 +/- 0.007 kg/cm2, n greater than or equal to 55, P less than 0.05). The components of tension at optimal length were similar for all gastric muscles (P greater than 0.1). The pylorus maintained less total tension (0.335 +/- 0.003 kg/cm2) and a greater component of resting tension (75.6%) than gastric muscle (P less than 0.01). Substance P, cholecystokinin-8 (CCK-8), and neurotensin varied in potency and efficacy in circular muscle of the antrum, corpus, and inferior portion of the pyloric ring. Longitudinal muscle and the superior portion of pylorus responded poorly if at all to neuropeptides. Substance P- but not CCK-8- or neurotensin-induced contractions of gastric muscle were reduced by tetrodotoxin (TTX) and atropine (P less than 0.05). Substance P-induced pyloric contractions were TTX sensitive (P less than 0.05) but were unaffected by atropine. We concluded that 1) length-tension properties of gastric muscle are similar and distinct from the pylorus and that 2) neuropeptide efficacy varies regionally within the feline stomach and within the pylorus.
在体外等长条件下，比较了猫幽门肌和胃肌的力学特性及神经肽反应。胃窦环形肌的总张力（0.699±0.003kg/cm²）低于胃体环形肌（1.597±0.007kg/cm²）或胃小弯和胃大弯的纵行肌（1.256±0.009和1.253±0.007kg/cm²，n≥55，P＜0.05）。所有胃肌在最佳长度时的张力成分相似（P＞0.1）。幽门肌的总张力（0.335±0.003kg/cm²）低于胃肌，且静息张力成分（75.6%）高于胃肌（P＜0.01）。P物质、胆囊收缩素-8（CCK-8）和神经降压素在胃窦、胃体和幽门环下部的环形肌中的效力和效能各不相同。纵行肌和幽门上部对神经肽的反应很差或根本无反应。河豚毒素（TTX）和阿托品可降低P物质而非CCK-8或神经降压素诱导的胃肌收缩（P＜0.05）。P物质诱导的幽门收缩对TTX敏感（P＜0.05），但不受阿托品影响。我们得出结论：1）胃肌的长度-张力特性相似，与幽门不同；2）神经肽的效能在猫胃内和幽门内存在区域差异。
