Temperature-dependency of pacemaker activity in gastric smooth muscle

在离体豚鼠胃平滑肌组织中，研究了温度变化及其代谢抑制剂对慢波的调节作用，以了解代谢过程可能参与胃平滑肌组织自发活动的起搏器活动。实验记录了豚鼠胃平滑肌组织小块在24 ~ 42℃温度变化过程中，圆形、纵向平滑肌细胞和Cajal间质细胞自发产生的电反应。随着温度的升高，慢波电位、跟随电位和起搏器电位的频率和上升速度增加，而这些电位的持续时间缩短。这些变化与气温升高呈线性关系。在24 ~ 32℃之间，慢波第二分量产生的延迟时间呈指数型下降，而在32℃以上则保持不变。静息膜电位和慢波振幅对温度不敏感。温度协同效率（Q10值）的计算表明，慢波的频率、持续时间和上升速率都较高。氰化钾（KCN）是一种线粒体代谢活性抑制剂，仅抑制慢波频率的变化，而不抑制慢波持续时间和上升时间的速率。这些结果表明，单独决定慢波频率的因素与线粒体代谢活性有因果关系。由于KCN没有改变慢波的持续时间和上升速度，因此在测定慢波时考虑了线粒体代谢以外的因素。整个胃的活动调节可能是最活跃的区域，发现它是胃的主体区。体区每分钟产生4-6次慢波，它们具有很强的潜在依赖性，表明可能有线粒体以外的因素参与了活性的调节。少

In isolated gastric smooth muscle tissue of the guinea-pig, the effects of changes in temperature and their modulation by metabolic inhibitors on slow waves were investigated, to understand the possible involvement of metabolic processes in the pacemaker activity of spontaneous activity of gastric smooth muscle tissues. Experiments were carried out to record spontaneously generating electrical responses from circular and longitudinal smooth muscle cells and interstitial cells of Cajal, in small pieces of gastric smooth muscle tissues isolated from the guinea-pig, during changing temperature between 24 and 42 ℃. With elevation of temperature, the frequency and the speed of rate of rise were increased in slow waves, follower potentials and pacemaker potentials, while the duration of these potentials was reduced. These changes were related with the elevation of temperature in a linear way. The latency for generating the 2nd component of slow wave was decreased in an exponential way betwee … More n 24 and 32 ℃, while it remained unchanged above 32 ℃. The resting membrane potential and amplitude of slow waves were not sensitive to temperature. Calculation of temperature co-efficiency (Q10 value) indicated that it was higher on the frequency, duration and rate of rise of slow waves. Potassium cyanide (KCN), an inhibitor of mitochondrial metabolic activity, inhibited only the changes in frequency, but not the duration and rate of rise time, of slow waves in response to temperature. These results suggested that the factors determining the frequency of slow waves alone are causally related to the mitochondrial metabolic activity. As the duration and the rate of rise time of slow waves were not altered by KCN, possible contribution of factors other than mitochondrial metabolism was considered for their determination. The regulation of the activity of entire stomach might be the most active region, and it was found to be the corpus region of the stomach. The corpus region produced slow waves 4-6 times every min, and they had strong potential-dependency, suggested a possible involvement of factors other than mitochondria for regulation of the activity. Less