Krishnamurti C R, Kitts D D, Kitts W D, Tompkins J G
J Reprod Fertil. 1982 Jan;64(1):59-67. doi: 10.1530/jrf.0.0640059.
Myoelectrical activity in the uterus of late-pregnant sheep was recorded by the chronic implantation of bipolar electrodes in the myometrium. Three distinct patterns of electrical activity were recognizable: irregular trains of action potentials (greater than 120 sec), long spike bursts (7--120 sec), or short spike bursts (less than 7 sec) each exhibiting high (greater than 100 muV) or low (50--100 muV) amplitude. The duration of spike activity was expressed as the myoelectrical index (MI), i.e. the fraction of the hour during which a given category of activity is exhibited. The increase in the overall MI which represents daily average values regardless of the class of amplitude from 72 h pre partum up to parturition was significantly (P less than 0.05) more pronounced in the uterine horn than in the body of the uterus. During the last 6--7 days of gestation high-amplitude irregular trains and long spike bursts were significantly (P less than 0.05) more frequent than these activity patterns with low amplitude. Regardless of the amplitude, the incidence of irregular trains began to decline rapidly 48 h pre partum with an abrupt cessation following parturition. The frequency of long spike bursts increased 72 h pre partum to reach a maximum which coincided with parturition.
通过在妊娠晚期绵羊子宫肌层长期植入双极电极来记录子宫的肌电活动。可识别出三种不同的电活动模式：不规则的动作电位序列（大于120秒）、长的尖峰爆发（7 - 120秒）或短的尖峰爆发（小于7秒），每种模式均表现出高幅度（大于100微伏）或低幅度（50 - 100微伏）。尖峰活动的持续时间用肌电指数（MI）表示，即呈现给定活动类别的每小时的比例。代表从产前72小时到分娩的每日平均值的总体MI的增加，在子宫角比子宫体中显著（P小于0.05）更明显。在妊娠的最后6 - 7天，高幅度的不规则序列和长的尖峰爆发比低幅度的这些活动模式显著（P小于0.05）更频繁。无论幅度如何，不规则序列的发生率在产前48小时开始迅速下降，产后突然停止。长的尖峰爆发的频率在产前72小时增加，达到与分娩同时出现的最大值。
