NEUROPEPTIDE-CONTAINING AXON TERMINALS IN THE MALE-RAT MAJOR PELVIC GANGLION ARE PRIMARILY OF SACRAL ORIGIN

The major pelvic ganglion of the male rat supplies the lower bowel and urogenital tract and contains both sympathetic and parasympathetic neurons. Many axon terminals in this ganglion contain peptides and the aim of the present study was to determine whether these are of sympathetic (i.e., lumbar) or parasympathetic (i.e., sacral) origin. The distribution of terminals containing various peptides following bilateral lesion of the hypogastric or pelvic nerves was compared with that in control animals. The majority of peptide-containing terminals were associated with non-noradrenergic neurons and were found to arise from the pelvic nerves. These projections were the almost exclusive origin of somatostatin-, cholecystokinin- and enkephalin-immunoreactive terminals, whereas galanin-immunoreactive terminals originate from both the hypogastric and pelvic nerves. Thus neuropeptides are useful markers for many parasympathetic terminals in the male rat major pelvic ganglion but no neuropeptides that are markers for the majority of sympathetic terminals have yet been identified.