The analysis of drug-induced tremor in mice.

An improved method of recording tremor in mice has been developed using a gramophone pick-up and a cathode ray oscillograph. Permanent records are made on 35 mm. film from which it is possible to determine qualitative differences in the tremor caused by various drugs. In addition, the severity of the tremor may be estimated quantitatively by a tremor index. The rate and variations in the rhythm and amplitude and in the tremor index have been determined for Tremorine (1,4-dipyrrolidin-1'-ylbut-2-yne), harmine, harmaline, 3-amino-1,1,3-triphenylpropan-1-ol and lysergic acid diethylamide. The incidence of side effects has also been noted.