Pronociceptive effect of 5-HT1A receptor agonist on visceral pain involves spinal N-methyl-d-aspartate (NMDA) receptor

► 5-HT1A receptor agonist DPAT produces pronociceptive effects in visceral pain. ► DPAT activates of presynaptic 5-HT1A receptors to inhibit GABA release. ► Inhibition of GABAergic neurons unmasks the excitatory glutamatergic system. ► This effect results in visceral hyperalgesia in behavioral studies. ► The electrophysiology experiments also confirm the findings of behavioral studies.