Intermittent tremor-bursts induced by chlorpromazine and pentobarbitone in guinea pigs: a new tremor model.

It was discovered by serendipity that a combined application of chlorpromazine (3.5 mg/kg) and pentobarbitone (20.0 mg/kg) induced intermittent tremor-bursts in four extremities of guinea pigs. This tremor with a prominent extensor activity disappeared after spinalization, indicating a supraspinal process. Biperiden reduced the frequency and amplitude of the tremor, which was further diminished by amantadine. Baclofen was found to be most potent drug in suppressing tremor. It was suggested that the cortico-striato-pallido-thalamo-cortical feedback loop may be impaired by a combined action of chlorpromazine and pentobarbitone. This new animal model for drug-induced tremor would be of considerable importance with regard to physiological, biochemical, pharmacological and pathological aspects of motor control.