Fig. 9.
Fast and slow EPSPs evoked in submucosal neurons by mechanical stimulation of the mucosa are mediated by 5-HT1P receptors. A, A prolonged slow EPSP is evoked in a submucosal neuron by application of a mechanical stimulus to the mucosa (underline). The neuron becomes excited during the response and discharges a burst of action potentials. B, In a different preparation from another animal, a small slow EPSP and bursts of fast EPSPs are evoked by the delivery of a mechanical stimulus (underline) to the mucosa. Both slow and fast EPSPs are reversibly inhibited by 5-HTP-DP. Both slow and fast EPSPs recover after the washout of 5-HTP-DP. The responses are then reversibly inhibited by tropisetron (1 μm) and again recover after the washout of the drug.