CHEMICAL CODING OF NEURONS PROJECTING TO PELVIC VISCERA IN THE MALE GUINEA-PIG - A STUDY BY RETROGRADE TRANSPORT AND IMMUNOHISTOCHEMISTRY

Retrograde transport studies using Fast Blue dye demonstrated that the ductus deferens, seminal vesicle, prostate and rectum, but not the ur inary bladder of the male guinea pig are at least in part innervated b y the anterior major pelvic ganglion. In the ductus deferens, seminal vesicle and prostate innervation is derived from ipsilateral and contr alateral ganglia. In addition to retrograde studies, dye-filled neuron s were analysed immunohistochemically for neuronal markers and associa tions with specifically identified neuronal projections. Neurons of th e ganglion projecting to the ductus deferens either contained tyrosine hydroxylase alone, tyrosine hydroxylase and neuropeptide Y, neuropept ide Y alone, neuropeptide Y and vasoactive intestinal peptide, or vaso active intestinal peptide alone. These neurons were associated with th ree classes of neuronal projections, substance P-, leucine-enkephalin- , and methionine-enkephalin-immunoreactive. Neurons projecting to the seminal vesicles were similar to the neurons supplying the ductus defe rens, except none of the seminal vesicle-specific neurons exhibited va soactive intestinal peptide immunoreactivity. Neurons supplying the pr ostate were immunoreactive for either tyrosine hydroxylase or neuropep tide Y, these neurons were infrequently associated with the three clas ses of varicose neuronal projections. Neurons projecting to the rectum contained neuropeptide Y and were only associated with methionine-enk ephalin immunoreactive neuronal projections in one animal.