Fig. 12.
Analysis of the uptake of the activity probe FM2-10 suggests that CGRP-mediated neurotransmission is necessary for the spread of excitation in the submucosal plexus after the delivery of a mechanical stimulus (stroking) to the mucosa. The intact mucosal surface was gently stroked to activate submucosal primary afferent neurons counted in surviving preparations of mucosa–submucosa. FM2-10 was present and used as a neuronal activity probe. The number of submucosal neurons taking up FM2-10 was determined in nonstroked and stroked regions. Under control conditions, the number of neurons taking up FM2-10 was greatly increased by stroking the mucosa. The effect of stroking was blocked by the CGRP antagonist hCGRP8–37.