title: Capsaicinoid-induced local and systemic antinociception without substance P depletion.
abstract: Capsaicin and its analog, dihydrocapsaicin, produced chemogenic and thermal antinociception and depletion of substance P from the dorsal spinal cord and dorsal root ganglia of guinea pigs following a single parenteral dose. Time course and distribution studies indicated that capsaicinoid-induced antinociception resulted from neither depletion of substance P nor nonspecific actions of capsaicinoids at dorsal root ganglia. A site of action for capsaicinoid-induced antinociception is peripheral to the dorsal root ganglia and may involve covalent binding of capsaicinoids to free nerve endings of the dermis. Depletion of substance P by capsaicinoids appears to be mediated at a site more central than that which mediates antinociception and may involve alterations in the retrograde axoplasmic transport of neurotrophic factors.
mesh_terms: D000344:Afferent Pathways / Q000187:drug effects / Q000378:metabolism; D000818:Animals; D002211:Capsaicin / Q000031:analogs & derivatives / Q000494:pharmacology*; D003342:Corpus Striatum / Q000187:drug effects / Q000378:metabolism; D005231:Fatty Acids, Unsaturated / Q000494:pharmacology*; D005727:Ganglia, Spinal / Q000187:drug effects / Q000378:metabolism; D006168:Guinea Pigs; D007031:Hypothalamus / Q000187:drug effects / Q000378:metabolism; D009619:Nociceptors / Q000187:drug effects* / Q000378:metabolism; D012867:Skin / Q000294:innervation; D013116:Spinal Cord / Q000187:drug effects / Q000378:metabolism; D013373:Substance P / Q000378:metabolism*
chemical_list: D005231:Fatty Acids, Unsaturated; D013373:Substance P; D002211:Capsaicin; C012906:dihydrocapsaicin