[Responses between iris sphincter and dilator evoked by cholinergic nerve stimulation]

Responses of bovine iris sphincter and dilator evoked by electrical stimulation were recorded in vitro. In order to examine the time course of the iris sphincter and the dilator, the two muscle strips were investigated under the same conditions; i.e., the iris sphincter and the dilator were immersed in parallel in a 0.5 ml organ bath, thus perfused with the same fluid and stimulated by the same electrical pulses. Remarkable difference was found in the time courses between the iris sphincter and the dilator, and this difference was discussed in relation to pupil movement.