Figure 6. Effects of blocking neurotransmission on anally evoked responses.

A, Ca²⁺ responses in 9 neurons to anal mucosal stimulation. Note that during the CMMC the prolonged excitatory responses (neurons 1, 2, 3, 5, and 6) were somewhat variable in both duration and onset, as were the inhibitory responses (neurons 4, 7, 8, 9). However, following hexamethonium (100 μm) the responses in all neurons to stimulation were blocked, although their prestimulus activity continued. B, anal stimulation of the mucosa evoked responses in several myenteric neurons after nicardipine (1 μm), which abolished responses in the muscle. Note: dotted lines indicate where CMMC is likely to be occurring. Following the further addition of TTX (1 μm) all spontaneous and evoked Ca²⁺ transients in these neurons were abolished.