Figure 3. Changes in visceromotor response evoked by focal electrical stimulation of the exposed colorectum in ls/ls mice.

A, electromyographic responses evoked by calibrated tail pinch and hindlimb pinch did not differ between C57BL/6 and ls/ls mice. B, averaged responses to tail or hindlimb pinch for C57BL/6 and ls/ls mice showed no significant differences. C, focal electrical stimulation (1 Hz, 0.4 ms, 60 V, 10 s) of the surface of the exposed control rectum elicited brief visceromotor responses with latencies of ∼50 ms. D, VMRs elicited from the aganglionic colorectum were of reduced intensity. E, the average number per second of multiunit action potentials were significantly reduced in ls/ls mice.