The antinociceptive effect of moclobemide on the vocalization threshold to paw pressure in a rat model of unilateral mononeuropathy

The aim of our study was to investigate the antinociceptive activity of moclobemide on the vocalization threshold to paw pressure in a rat model of unilateral mononeuropathy. The neuropathy was produced by ligation of the sciatic nerve and nociceptive thresholds were determined 15-21 days after surgery by a modification of the Randall-Sellito method. Group 1 (n = 10) received 0.2 ml peroral (p.o.) saline, Group 2 (n = 10) 5 mg kg(-1), Group 3 (n = 10) 10 mg kg(-1) and Group 4 (n = 10) 20 mg kg(-1) p.o. moclobemide. Nociceptive pressure thresholds were then measured every 20 minutes after drug administration. Analysis of variance, Tukey's test and a paired Student's t-test were employed for statistical analysis. The perorally administered moclobemide (5, 10 and 20 mg kg(-1)) produced an antinociceptive effect on both lesioned and non-lesioned hind paws (P < 0.05). However, the analgesic effect on the lesioned paw was significantly more potent than the non-lesioned paw. The peak value (p) remained constant while the maximal increment between the control threshold and the peak value (I-max) was significantly more pronounced for the lesioned paw (P < 0.001). The results of this study may suggest that moclobemide can be a therapeutic alternative to treat some clinical symptoms in peripheral neuropathic conditions. (C) 2001 Academic Press.