[Acute effects of intrathecal capsaicin and substance P on nociceptive thresholds in rats].
We have compared the effects of a single intrathecal injection of capsaicin or substance P (SP) on the motor responses to radiant heat and electrical nociceptive stimulations in the Rat. With nociceptive electrical stimulation, an immediate hyperalgesia followed capsaicin injection in all Rats. On the other hand, some Rats displayed hyperalgesia after SP while others showed hypoalgesia. Both capsaicin and SP, induced hypoalgesia to radiant heat in 17 rats. In 5 rats no response was obtained.
D000818:Animals; D002211:Capsaicin / Q000494:pharmacology*; D004558:Electric Stimulation; D006358:Hot Temperature; D007278:Injections, Spinal; D008297:Male; D009619:Nociceptors / Q000187:drug effects*; D051381:Rats; D012684:Sensory Thresholds / Q000187:drug effects; D013373:Substance P / Q000494:pharmacology*
D013373:Substance P; D002211:Capsaicin
Effets aigus de la capsaïcine et de la substance P intrathécale sur les seuils nociceptifs chez le rat.