A, pERK-LI neurons in the NTS; B, GABA-LI neurons in the NTS; C, pERK-LI neurons with GABA immunoreactivity; D, pie chart showing the distribution of the GABA-LI and GABA-negative pERK-LI neurons in the NTS. White arrows in A indicate pERK-LI neurons, those in B indicate GABA and those in C indicate GABA and pERK-LI neurons. The open arrows in A and C indicate pERK-LI neuron without GABA immunoreactivity. The arrowhead in B indicates pERK negative/GABA positive. The star in A corresponds to the arrowhead in B and C, and that in B corresponds open arrows in A and C. E and F, mean number of swallows in vehicle-treated rats and that following microinjection of muscimol or bicuculline to the NTS, and that following microinjection of vehicle or bicuculline to the NTS in capsaicin-treated rats. *P < 0.05, **P < 0.01.