Long lasting inhibition of horseradish peroxidase (HRP) transport in sensory nerves induced by capsaicin pretreatment of the receptive field.
Capsaicin, when injected into the scrotal skin of adult rats was seen to produce a long-lasting desensitization. To investigate the possible effect of this treatment on the sensory neurones of the pudendal nerve, rats were injected with horseradish peroxidase (HRP) at different time intervals following pretreatment with capsaicin. The HRP was applied in two different ways. In one group of rats HRP was injected into both sides of the scrotal skin between 2 and 12 days after capsaicin pretreatment of one side of the scrotal skin. More HRP labelled neurones were seen in the S1 and L6 dorsal root ganglia (DRG) on the non-treated side than on the pretreated side. Similar results were obtained when the HRP was injected directly into the pudendal nerve. A marked decrease in the number of HRP labelled neurones on the pretreated side was observed even when HRP was injected into the nerve up to 1 year after the capsaicin pretreatment. It appears therefore that at least part of the effect of capsaicin on peripheral sensory neurones is due to an effect of capsaicin on the axoplasmic transport processes, and that this effect is long lasting.
D000818:Animals; D001370:Axonal Transport / Q000187:drug effects*; D002211:Capsaicin / Q000494:pharmacology*; D003864:Depression, Chemical; D008297:Male; D009475:Neurons, Afferent / Q000187:drug effects; D010525:Peripheral Nerves / Q000187:drug effects*; D051381:Rats; D011919:Rats, Inbred Strains; D012611:Scrotum / Q000294:innervation; D012867:Skin / Q000294:innervation
D002211:Capsaicin