Mayrand S, Tremblay L, Diamant N
Department of Medicine, University of Toronto, Ontario, Canada.
Am J Physiol. 1994 Nov;267(5 Pt 1):G914-21. doi: 10.1152/ajpgi.1994.267.5.G914.
Using an isotonic recording device (barostat), we assessed feline esophageal smooth and striated muscle tone in vivo and determined the effects of a cholinergic agonist (bethanechol) and antagonist (atropine) and the effect of body position on this tone. Studies were performed on six cats under light intravenous ketamine anesthesia. Two parameters were analyzed: compliance and resistance to initial stretch (resting tone). Smooth muscle compliance (0.51 +/- 0.03 ml/mmHg) was significantly greater than that of the striated muscle section (0.26 +/- 0.02 ml/mmHg; P = 0.0260). Resting tone was low in both esophageal sections. Neither atropine nor bethanechol had any significant effect on the two tone parameters measured in smooth muscle. Change in body position had no influence on the intraesophageal balloon volume. We conclude that esophageal wall compliance varies according to location (smooth vs. striated muscle) and that esophageal smooth muscle tone is not under cholinergic excitatory control. Isotonic recording in vivo should allow further investigations of the nature of the neural and myogenic control of esophageal tone and of the relationships between phasic and tonic activity.
我们使用等张记录装置（压力调节器）在体内评估猫食管平滑肌和横纹肌的张力，并确定胆碱能激动剂（氨甲酰甲胆碱）和拮抗剂（阿托品）的作用以及体位对这种张力的影响。在轻度静脉注射氯胺酮麻醉下对6只猫进行研究。分析了两个参数：顺应性和对初始拉伸的阻力（静息张力）。平滑肌顺应性（0.51±0.03 ml/mmHg）显著大于横纹肌部分（0.26±0.02 ml/mmHg；P = 0.0260）。两个食管部分的静息张力均较低。阿托品和氨甲酰甲胆碱对平滑肌中测量的两个张力参数均无显著影响。体位变化对食管内气囊体积没有影响。我们得出结论，食管壁顺应性因位置（平滑肌与横纹肌）而异，并且食管平滑肌张力不受胆碱能兴奋控制。体内等张记录应有助于进一步研究食管张力的神经和肌源性控制的性质以及相位和紧张性活动之间的关系。
