All pelvic neurons in male rats contain immunoreactivity for the synthetic enzymes of either noradrenaline or acetylcholine.

The pelvic ganglia contain sympathetic and parasympathetic neurons that supply the lower urinary and digestive tracts and internal reproductive organs. Although synthetic enzymes for noradrenaline have been previously identified in about one-third of these neurons, until very recently the methodology has not been available to directly determine whether all of the remaining neurons are cholinergic. The present immunohistochemical study has used a new antibody directed against a peptide fragment of choline acetyltransferase (ChAT) to identify pelvic cholinergic neurons. The results show that all pelvic neurons are either noradrenergic or cholinergic (as seen by the presence of tyrosine hydroxylase (TH) or ChAT, respectively). Neurons containing neither or both enzymes are extremely rare. It is concluded that the neuropeptides found in most pelvic neurons coexist with either noradrenaline or acetylcholine and may be involved in cotransmission in the pelvic viscera.