[Iontophoretic atropine attenuates the inhibitory effect of stimulating SmI on nociceptive responses of pf neurons].

Using the techniques of multimicropipette and iontophoresis, we observed whether ACh was involved in the cortical descending modulation of Pf neurons in rats. It was shown that the inhibition elicited by stimulation of the sensorimotor area (SmI) was attenuated after microiontophoretic atropine and that the nociceptive responses of Pf neurons were obviously reduced by microiontophoretic ACh. Therefore, it suggests that ACh may be considered as one of the neurotransmitters involved in the descending modulation of pain.