Figure 7.

Somatostatin affects spontaneous and induced myenteric neuron activity. Somatostatin (0.65–1.00 μmol/L) strongly depressed both spontaneous Ca²⁺ transients and responses to DMPP in Chat⁺/GCaMP6f⁺ colonic myenteric neurons. (A and B) A 3D plot showing that somatostatin strongly depresses the frequency of spontaneous Ca²⁺ transients recorded from ChAT⁺/GCaMP6f⁺ colonic myenteric neurons without an appreciable effect on amplitude or kinetics (rise and decay time). Ca²⁺ transients from 1800 simultaneous recordings from 12 neurons are shown (A) before and (B) 20 minutes after application of somatostatin. (C and D) Somatostatin depresses DMPP-evoked Ca²⁺ responses recorded from Chat⁺/GCaMP6f⁺ colonic myenteric neurons. Simultaneous responses evoked by rapid puffer perfusion of DMPP from 10 neurons are shown (C) before and (B) 20 minutes after bath application of somatostatin. (E) Somatostatin depresses the response to DMPP by 50%. Ca²⁺ transients were measured in 50 control neurons and 45 neurons treated with somatostatin (N = 3). Induced activity was measured in 30 control (+DMPP) and 30 treated (DMPP + somatostatin) neurons (N = 2) in the proximal colon (Figure 2B1).