Computer evaluation of the effect of urecholine on the spontaneous activity of smooth muscle from the urinary bladder of the rabbit.

The spontaneous activity exhibited in vitro by smooth muscle strips from the urinary bladder of the rabbit under the influence of Urecholine in concentrations from 0.3 to 30 muM has been characterized in terms of three parameters: mean tension, frequency of contraction, and contractile deviation, all obtained by computer an alysis. While mean tension and frequency monotonically increased with concentration, the contractile deviation rose to a peak in the vicinity of 3.0 to 6.0 muM and thereafter decreased. At concentrations less than 10 muM the contractile patterns were almost periodic, while at 10 and 30 muM, the patterns became highly erratic. Histologic examination of a limited number of tissues showed longitudinally oriented muscle bundles with multiple anastomosing.