Fig. 2.

Schedule of drug treatment and experimental processes. (a) PF (100, 200, 500 nmol, i.c.v.) was administered 15 min before intraplantar injection of 20 μl 1% formalin. MK-801 (14.8 pmol, i.t.) was injected 5 min before intraplantar formalin injection. (b) PF (100, 200, 500 nmol, i.c.v.) was administered 150min before intrarthecal injection of EAA agonists (in 5 μl ACSF). MK-801 (14.8 pmol, i.t.) and NBQX (5 nmol) were injected 5 min before intrathecal injection of EAA agonists. The time spnet on biting or scretching induced by EAA agonists was observed and recorded during the first 2 min. (c) PF (100, 200, 500 nmol, i.c.v.) were administered 15 min and 5 min intrathecal injection of morphine, respectively. Mice were intrathecally administered morphine (250 nmol). The onset and the total number of clonic seizure-like excitatory behavior were observed and recorded for 60 min