Involvement of N-methyl-d-aspartate (NMDA) receptors in a rat model of visceral hypersensitivity.

N-Methyl-d-aspartate (NMDA) is known to be involved in the transmission of nociceptive information. In the present study, we investigated the effect of peripheral and central NMDA receptor antagonist MK-801 in visceral hypersensitivity. In an animal model of colorectal distension (CRD), administration of both intrathecal MK-801 (1.5 nmol) and intraperitoneal MK-801 (0.15 mg/kg) completely abolished the CRD-induced visceral hypersensitivity of noxious and innocuous stimuli. Thus, the results from this experiment demonstrate the efficacy of MK-801 in blocking the visceral hypersensitivity mediated by central and peripheral mechanisms.