Involvement of GABAB receptor in the antihypersensitive effect in anterior cingulate cortex of partial sciatic nerve ligation model

The role of the GABAB receptor in the anterior cingulate cortex (ACC) of neuropathic pain is unclear. Injection of a GABAB receptor antagonist CGP35348 into the ACC induced mechanical hypersensitivity in normal rats. Activation of the GABAB receptor injected by a GABAB receptor agonist baclofen into the ACC attenuated mechanical hypersensitivity in partial sciatic nerve ligation (PSNL) rats. Co-microinjection of CGP35348 with a muscarinic M1 receptor agonist McN-A-343 into the ACC significantly inhibited McN-A-343-induced antihypersensitivity in PSNL rats. These results suggest that the GABAB receptor in the ACC contributes to mechanical hypersensitivity and is involved in muscarinic M1 receptor-mediated antihypersensitivity.