Biancani P, Zabinski M P, Kerstein M D, Behar J
Gastroenterology. 1980 Feb;78(2):301-9.
In vitro force-length curves of rings from the gastroduodenal junction were obtained in standard tyrode solution, in tyrode with 140 mM KCl, and in calcium-free tyrode with 5 mM sodium EDTA, to determine basal, total, and passive forces, respectively. Active force was obtained as a difference between total and passive forces. Basal, total, passive, and active forces were higher for pyloric rings than for duodenal and antral rings. Furthermore, in the pylorus the force-length curves were shifted to the left along the length axis due to a narrowing at the gastroduodenal junction. Pressure-diameter relationships calculated from the in vitro force-length data and compared with previously determined in vivo pressure-diameter data, demonstrated good correlation between the in vivo and in vitro data. These data indicate that the higher forces and pressures observed in the pylorus are due to a combination of higher active and passive components. At low levels of stretch, the active forces are higher, while at high levels of stretch the passive forces become prevalent. These data suggest that, because of its passive properties the pylorus may act as a stricture and resist opening to large diameters, thus impeding the passage of large boluses. Near closure, however, any pressure gradient at the gastroduodenal junction would be due to active contraction of the pyloric circular muscles, and thus be susceptible to modulation through neural and/or myogenic factors.
在标准台氏液、含140 mM氯化钾的台氏液以及含5 mM乙二胺四乙酸钠的无钙台氏液中，分别获取胃十二指肠连接处环的体外力-长度曲线，以测定基础力、总力和被动力。主动力通过总力与被动力之差获得。幽门环的基础力、总力、被动力和主动力均高于十二指肠环和胃窦环。此外，由于胃十二指肠连接处变窄，幽门处的力-长度曲线沿长度轴向左移动。根据体外力-长度数据计算出压力-直径关系，并与先前测定的体内压力-直径数据进行比较，结果表明体内和体外数据之间具有良好的相关性。这些数据表明，在幽门处观察到的较高力和压力是由于较高的主动成分和被动成分共同作用的结果。在低拉伸水平时，主动力较高，而在高拉伸水平时，被动力占主导。这些数据表明，由于其被动特性，幽门可能起到狭窄作用，抵抗扩张至大直径，从而阻碍大食团通过。然而，在接近关闭时，胃十二指肠连接处的任何压力梯度都将归因于幽门环形肌的主动收缩，因此易受神经和/或肌源性因素的调节。
