抄録
An attempt was made to identify the electrical property of the circular smooth muscle of the pregnant mouse uterus and to find out the functional interaction between the longitudinal and circular muscle layers.
1. In contrast to the spike potentials which dominate the electrical activity of the longitudinal muscle, slow potential was predominant in the circular muscle. Resting potential, length constant and conduction velocity of circular muscles were-55 mV, 1.2-1.5 mm and 0.5-1 cm/sec, respectively. Length constant and conduction velocity was 3 mm and 20 cm/sec, respectively, for the longitudinal muscle.
2. Coincidental discharge occurred in the circular muscle when the longitudinal muscle contracted spontaneously and vice versa, the feature being unaffected by the treatment with tetrodotoxin. Taking the contraction as representative of the generation of excitation, the result may suggest a myogenic conduction of the excitation between the longitudinal and circular muscles.
