Immunohistochemical Characteristics and Distribution of Neurons in the Paravertebral, Prevertebral and Pelvic Ganglia Supplying the Urinary Bladder in the Male Pig

The distribution and chemical coding of neurons supplying urinary bladder in the male pig were studied in the sympathetic chain ganglia, inferior mesenteric ganglia and anterior pelvic ganglia. The combined retrograde tracing and immunohistochemistry for tyrosine hydroxylase (TH), dopamine beta-hydroxylase (DBH), neuropeptide Y (NPY), somatostatin (SOM), galanin (GAL), vasoactive intestinal polypeptide (VIP), nitric oxide synthase (NOS), calcitonin gene-related peptide (CGRP), substance P (SP), choline acetyltransferase (ChAT) and vesicular acetylcholine transporter (VAChT) were applied in the experiment. Bladder-projecting neurons were found in all the ganglia studied. The majority of sympathetic ganglia neurons (inferior mesenteric ganglia and sympathetic chain ganglia) expressed immunoreactivity (IR) to DBH. In sympathetic chain ganglia these neurons simultaneously expressed NPY, GAL or VAChT, while in inferior mesenteric ganglia they contained NPY, SOM and/or GAL. A small number of these bladder-projecting neurons was VAChT-IR and some contained NPY. In the pelvic ganglia bladder-projecting neurons formed two populations: DBH- and VAChT-IR. Some of DBH-IR neurons contained IR to NPY, SOM or GAL, while VAChT-IR neurons were NPY-, SOM- or NOS-IR. The results indicate that sympathetic ganglia contain mainly adrenergic neurons, while pelvic ganglia contain both adrenergic and cholinergic neurons. All these neurons contain typical combinations of neuropeptides.