Effect of ketamine on spatial learning and memory in a rat model of incisional pain / 中华麻醉学杂志

ABSTRACT

Objective To investigate the effect of ketamine on spatial learning and memory in a rat model of acute pain produced by an incision in plantar area. Methods Seventy-two 3-month old male SD rats weighing 200-250g were randomly divided into 3 groups (1) control group (C) received no plantar incision (n = 24); (2) acute pain group (M) received an incision in the sole of the hindpaw according to the method described by Brennan (n = 24) and (3) ketamine group (K) received plantar incision and intraperitoneal ketamine 10 mg?kg-1 every day for 7 days starting from the day when plantar incision was made ( n = 24). In group C and M normal saline (NS) was given i.p. instead of ketamine. The three groups were further divided into 2 subgroups according to the time when Morris water maze (MWM) testing was started-1 week (C1, M1,K1) or 3 weeks (C3, M3, K3) after plantar incision. MWM test was performed 4 times a day for 6 consecutive days. The latent periods and swimming distances were recorded automatically by MWM monitoring system. Six days after the last MWM testing the animals were anesthetized and killed. The hippocampus was removed for microscopic examination. Results (1) MWM test From the 1st to the 6th day of testing, the latent period and swimming distance in group K1 were significantly longer than those in group C1 and M1 (P