Figure 7. Ca²⁺ activity in NOS +ve neurons.

A, between CMMCs, the activity in NOS +ve neurons occurred in regular bursts (neurons 1–4; see left hand panel). Following anal mucosal stimulation there was a brief increase in burst activity in most of these neurons (see neurons 1, 2 and 4; right hand panel), except neuron 3 just before the onset of the CMMC. During the CMMC all these neurons decreased their activity. B–E, responses of NOS +ve neurons to anal mucosal stimulation in another preparation. B, left hand panel shows the location of NOS +ve neurons (arrows) in two ganglia. Right hand panel shows the average Ca²⁺ activity of neurons within these ganglia. C, NOS +ve neurons (1–5) decreased their activity during the CMMC following anal mucosal stimulation, whereas others (neurons 6–8) appeared to be unchanged by the stimulus. These neurons had complex morphology, round or oval cell bodies with lamina dendrites (see their corresponding morphologies in D). Surprisingly, some NOS +ve neurons increased their firing during the CMMC. These neurons had a simple morphology exhibiting a ‘dew drop’ appearance (see corresponding morphologies in D and E).