Effect of lidocaine on harmaline-induced tremors in the rat

The present study was undertaken to investigate the effect of lidocaine on harmaline-induced tremors in the rat. Four groups of Wistar rats weighing 4 5-50 g were injected with harmaline (50 mg/kg IF) for inducing experimental tremors. The rats in group 1 served as control, whereas the animals in gro ups 2, 3, and 4 were also given lidocaine IP at doses of 12.5, 25, and 50 m g/kg, respectively, 10 min after the onset of tremors (therapeutic study). In a separate four groups of animals intraperitoneal lidocaine injection wa s given 10 min before harmaline (prophylactic study) in the same dose regim en as mentioned above. The latency of onset, intensity, and duration of tre mor and electromyographic responses were recorded. Lidocaine dose dependent ly attenuated harmaline-induced tremors in rats. The latency period was inc reased, and duration and intensity of harmaline-induced tremors was reduced by lidocaine. Our electromyography (EMG) study also revealed a decrease in the amplitude of harmaline-induced tremors in lidocaine-treated rats. In c onclusion, the results of this study clearly suggest beneficial effects of lidocaine in harmaline-induced tremors. (C) 1999 Elsevier Science Inc.