Activation of spinal serotonin(2A/2C) receptors augments nociceptive responses in the rat

The role of spinal 5-HT2A/2C receptors in the regulation of spinal nocicept ive transmission was studied. The 5-HT2A/2C agonist (+/-)-1-(2,5-dimethoxy- 4-iodophenyl)-2-aminopropane (DOI) and the antagonist ketanserin tartrate w ere administered intrathecally immediately before the formalin test. Activa tion of spinal 5-HT2A/2C receptors increased the pain-like behavioural resp onse in both the early and late phases. The findings support the hypothesis that spinal 5-HT2A/2C receptors augment the spinal afferent nociceptive im pulses induced by peripheral inflammation. (C) 2001 Elsevier Science BY. Al l rights reserved.