Regulation of substance P by nerve growth factor: disruption by capsaicin.
Capsaicin depleted substance P from guinea pig dorsal root ganglia and inhibited the retrograde axoplasmic transport of nerve growth factor (NGF). Doses of capsaicin which depleted substance P also inhibited the retrograde axoplasmic transport of NGF. Inhibition of the retrograde transport of NGF by capsaicin preceded substance P depletion. Supplementation of guinea pigs with mouse NGF completely prevented capsaicin-induced substance P depletion. It is concluded that capsaicin depletes substance P from primary afferent neurons of the adult guinea pig by altering the availability of NGF. The data support a role for NGF in the normal maintenance of neuropeptide levels in some sensory neurons in the adult animal.
D000818:Animals; D001370:Axonal Transport; D002211:Capsaicin / Q000494:pharmacology*; D004525:Efferent Pathways / Q000502:physiology; D005231:Fatty Acids, Unsaturated / Q000494:pharmacology*; D005727:Ganglia, Spinal / Q000187:drug effects / Q000502:physiology*; D006168:Guinea Pigs; D007700:Kinetics; D051379:Mice; D009414:Nerve Growth Factors / Q000494:pharmacology*; D013373:Substance P / Q000378:metabolism*
D005231:Fatty Acids, Unsaturated; D009414:Nerve Growth Factors; D013373:Substance P; D002211:Capsaicin