Figure 2. Recurrent production of ceramide during the organization of the GIR.
Recording of duodenal contraction (DC) and determination of ceramide content (Cer) on the nerve trunks were performed as in Fig. 1 following different treatments. Results are expressed as the percentage of control±SEM for each series of experiments. a, superfusion of the ganglion compartment with 6 µM C2-ceramide for 5 min. Ctrl, control; C2, C2-ceramide. b, superfusion of the nerve trunks compartment with 16 µM GW4869 for 30 min, then of the ganglion with 6 µM C2-ceramide. Ctrl-GW, control in the presence of GW; GW+C2, C2-ceramide in the presence of GW. c, GD performed before and after superfusion of the nerve trunks with 16 µM GW4869 for 30 min. Ctrl, control; GD, gastric distension; Ctrl-GW, control in the presence of GW; GD+GW , gastric distension in the presence of GW. d, recording of duodenal contractions before and after superfusion of the nerve trunks with 16 µM GW4869 for 30 min.Ctrl, control; GW, superfusion of the nerve trunks with GW. e, superfusion of the nerve trunks with 6 µM C2-ceramide in the presence of 3 µM tetrodotoxin. Ctrl-TTX, control in the presence of TTX; C2+TTX, C2-ceramide in the presence of TTX. f, superfusion of the nerve trunks with 6 µM C2-dihydroceramide. Ctrl, control; C2-dihydro, superfusion of the nerve trunks with C2-dihydroceramide. g, superfusion of the ganglion compartment with 6 µM C2-ceramide for 5 min. Ctrl, control; C2, superfusion of the coeliac plexus with C2-ceramide, . h, superfusion of the nerve trunks with sphingomyelinase (1 UI/100 µl). Ctrl, control; SMase, superfusion of the nerve trunks with SMase . Differences with control were significant in a Student's t test, *** p<0.001; ** p<0.01; * p<0.05 or non significant (ns).