Fig. 4.

The light>serotonin pathway activates enteric neurons in the stomach (sENs), which express nNOS and induce pyloric opening. a A schematic image of neuronal nitric oxide synthase (nNOS)-expressing enteric neurons (sENs; magenta) with axon-like structures around the pyloric sphincter (green) [23]. b The graph shows the pyloric opening rate in control and nNOS morphants under photoirradiation, the addition of serotonin, and the addition of SNAP. N = 3; n (control with no treatment) = 10, 21, 26; n (control with photoirradiation) = 14, 21, 28; n (control with serotonin) = 15, 12, 30; n (control with SNAP) = 21, 19, 13; n (nNOS morphants with no treatment) = 13, 11, 10; n (nNOS morphants with photoirradiation) = 21, 17, 20; n (nNOS morphants with serotonin) = 19, 26, 12; n (nNOS morphants with SNAP) = 63, 12, 29. Error bars show SE. c A schematic diagram of the light>pylorus signaling pathway in sea urchin larvae