Depletion by capsaicin of substance P-immunoreactivity and acetylcholinesterase activity from nerve fibres in the guinea-pig heart.
The sensitivity to capsaicin of substance P-immunoreactive nerve fibres in the hearts of guinea-pigs was examined. Capsaicin decreased considerably the substance P-immunoreactive material in nerve fibres of the parietal pericardium, atria, bicuspid and tricuspid valves. Pericardial and valvar nerve fibres localized by acetylcholinesterase (AChE) histochemistry had a distribution and density pattern similar to that of the substance P immunoreactive fibres. Capsaicin treatment also decreased the number of visible AChE-positive nerve fibres. It is known that capsaicin has a selective action on those substance P-immunoreactive fibres that are of sensory origin; thus, these results imply that substance P-immunoreactive fibres in the heart are sensory. Moreover, the results suggest that some of the nerve fibres localized in the heart by AChE histochemistry are substance P-containing sensory fibres.
D000110:Acetylcholinesterase / Q000378:metabolism*; D000818:Animals; D002211:Capsaicin / Q000494:pharmacology*; D005231:Fatty Acids, Unsaturated / Q000494:pharmacology*; D005260:Female; D006168:Guinea Pigs; D006321:Heart / Q000187:drug effects / Q000294:innervation*; D006892:Hydroxydopamines / Q000494:pharmacology; D008297:Male; D009412:Nerve Fibers / Q000187:drug effects / Q000378:metabolism*; D013373:Substance P / Q000378:metabolism*
D005231:Fatty Acids, Unsaturated; D006892:Hydroxydopamines; D013373:Substance P; D000110:Acetylcholinesterase; D002211:Capsaicin