Electrical activity of the isolated nerve-urinary bladder strip preparation of the rabbit

Abstract

The electrical activity of single cells of the smooth muscle of the isolated pelvic nerve-bladder strip preparation of the rabbit has been recorded by means of KCl-filled glass capillary microelectrodes. It was found that increasing the tension on the muscle either by stretching or by the addition of carbachol (3 µg/ml) to the bathing fluid causes a concomitant depolarization of the cell membrane. Spontaneous electrical activity and that elicited by stimulation of the nerve were similar and consisted of slow waves of depolarization of a 3–5 sec duration and spikes superimposed upon the depolarization phase of the slow wave. The spikes varied from 5 to 35 mv with no overshoot. Excitability of cells varied from one in which no response to tetanic stimulation of the nerve was seen to one which exhibited a series of spikes to a single shock. It was shown that slow waves and spikes could occur out of phase with the dominant activity of the whole muscle. Latency to a single shock to the nerve was found to be quite consistent for the same cell. However, a marked variation in latency was found among different cells of the same preparation.