title: Capsaicin treatment induces selective sensory degeneration and increased sympathetic innervation in the rat ureter.
abstract: Quantitative immunohistochemistry was used to study the innervation of the ureter in adult rats pretreated with capsaicin as neonates (50 mg/kg) or as adults (100-150 mg/kg, 10-22 days prior to being killed) using antibodies against protein gene-product 9.5, neuron-specific enolase, substance P, calcitonin gene-related peptide, neuropeptide Y, dopamine-beta-hydroxylase and vasoactive intestinal polypeptide. The number of calcitonin gene-related peptide- and substance P-containing fibres was reduced in the subepithelial plexus (adult capsaicin treatment < 1%, neonatal treatment < 5% of control), the submucosa (adult treatment < 11%; neonatal treatment < 51%) and in the smooth muscle layer and adventitia (adult treatment < 11%; neonatal treatment < 58%). Fibres immunoreactive for protein gene-product 9.5, a general neuronal marker, were reduced to 11% (adult treatment) or 0.5% (neonatal treatment) in the subepithelial plexus, but unchanged in the other layers, indicating a selective regional degeneration. In the smooth muscle layer the number of neuropeptide Y- and vasoactive intestinal polypeptide-containing nerve fibres was not altered by capsaicin. The number of neuropeptide Y fibres in the subepithelial plexus, however, was significantly increased after adult treatment (174% of control). After neonatal capsaicin treatment the intensity of the neuropeptide Y immunoreactivity was increased, more neuropeptide Y-positive nerve bundles were found and immunoreactive cell bodies were observed regularly in the adventitia of the ureter. The data indicate that capsaicin produces a selective degeneration of most afferent fibres in the subepithelial plexus of the rat ureter. This loss of capsaicin-sensitive afferent nerves evokes neuroplastic changes resulting in a hyperinnervation by neuropeptide Y-immunoreactive, presumably sympathetic fibres. The results suggest a mutual regulation of the pattern and density of innervation of peripheral target tissues by sensory and sympathetic neurons.
authors.affiliation: MPI Für physiologische und klinische Forschung, W. G. Kerckhoff-Institut, Nauheim, Germany.
authors.forename: H
authors.initials: H
authors.lastname: Sann
authors.forename: G
authors.initials: G
authors.lastname: Jancsó
authors.forename: A
authors.initials: A
authors.lastname: Ambrus
authors.forename: F K
authors.initials: FK
authors.lastname: Pierau
mesh_terms: D000818:Animals; D000906:Antibodies / Q000276:immunology; D002211:Capsaicin / Q000494:pharmacology*; D017950:Ganglia, Sensory / Q000187:drug effects*; D007150:Immunohistochemistry; D009410:Nerve Degeneration; D009412:Nerve Fibers / Q000276:immunology; D009478:Neuropeptide Y / Q000494:pharmacology; D051381:Rats; D011919:Rats, Inbred Strains; D013564:Sympathetic Nervous System; D014513:Ureter / Q000294:innervation*
chemical_list: D000906:Antibodies; D009478:Neuropeptide Y; D002211:Capsaicin