Capsaicin Treatment Induces Selective Sensory Degeneration and Increased Sympathetic Innervation in the Rat Ureter

Neuroscience. 1995 Aug;67(4):953-66. doi: 10.1016/0306-4522(95)00102-o.

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.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Antibodies / immunology
  • Capsaicin / pharmacology*
  • Ganglia, Sensory / drug effects*
  • Immunohistochemistry
  • Nerve Degeneration
  • Nerve Fibers / immunology
  • Neuropeptide Y / pharmacology
  • Rats
  • Rats, Inbred Strains
  • Sympathetic Nervous System
  • Ureter / innervation*

Substances

  • Antibodies
  • Neuropeptide Y
  • Capsaicin