Figure 5.

Properties of spontaneous depolarizations in longitudinal smooth muscles of the rabbit urethra. (Aa) Longitudinal smooth muscle of the urethra generated spontaneous depolarizations consisting of slow depolarizations and a superimposed spike-like depolarization. (Ba) In the same preparation that had been exposed to CPA for 30 min, spontaneous depolarizations were still generated. (Ab, Bb) In the presence of CPA, spontaneous depolarizations had a longer duration and the number of superimposed spike-potentials was increased. (C) After washing out CPA, control depolarizations were restored, and subsequent nicardipine (1 μM) abolished them.