Spontaneous electrical activity of the rat epididymis in vitro.

Smooth muscle electrical activity was recorded with suction electrodes from the partly or completely uncoiled epididymal duct of the rat in vitro. The electrical activity of the cauda epididymidis consisted of one or few spikes followed by a plateau of 1-2 sec. The frequency of electrical activity declined from the thicker-walled initial segment of the thin-walled initial segment, was increased to the level seen in the initial segment in the thicker, major portion of the caput epididymidis, declined in the corpus and fell steeply in the cauda epididymidis towards the vas deferens. Electrical activity spread over long distances in the distal cauda and epididymal vas. Elsewhere in the epididymis activity remained synchronous only for a short period in short segments.