1985 Volume 6 Issue 6 Pages 415-422
An immunoelectron microscopic study by the double staining protein A-colloidal gold method was performed on the neurons in the guinea-pig duodenum using specific antisera to neuropeptides, i.e. Met-enkephalin-Arg6-Gly7-Leu8 (Met-Enk-Arg-Gly-Leu), substance P (SP) and peptide-histidine-isoleucine (1-15) (PHI (1-15)). Immunoreactive neuropeptides existed in the cored vesicles of 80-110 nm in diameter. The immunopositive cored vesicles were present in both somata and processes of some neurons. Occurrence and projections of three subclasses of Met-Enk-Arg-Gly-Leu immunopositive neurons (Met-Enk-Arg-Gly-Leu neurons) were described. Somata of the Met-Enk-Arg-Gly-Leu neurons occurred in the myenteric ganglion. Processes of the Met-Enk-Arg-Gly-Leu neurons with immunoreactive SP projected to all the layers of the duodenal wall except the mucosa. Neuronal processes containing cored vesicles with both immunoreactive Met-Enk-Arg-Gly-Leu and PHI (1-15) were mainly distributed in the submucous plexus. None of them occurred around the duodenal gland. Neuronal processes containing cored vesicles with only immunoreactive Met-Enk-Arg-Gly-Leu were small in number. They were present in the circular muscle layer, deep muscular plexus and submucous plexus. Difference in the projections of the three subclasses of the Met-Enk-Arg-Gly-Leu neurons may indicate that each of them performs different functions.
