Abstract: Anisodine was administered to 4 groups of rabbits intraventricularly (5, 10, 15 and 20 mg). It was observed that 5 mg doses were effective to make the animals lose their righting reflexes. Increasing the dosage prolonged and aggravated the central depressant effect of anisodine.Following administraton of anisodine (10 mg), the duration of loss of righting reflex lasted 25.0±2.6 minutes. The combined use of anisodine with physostigmine (0.2mg i. v.), noradrenaline or adrenaline (100μg intraventricularly) induced loss of righting reflex of short duration, 15.1±3.2, 11.0±1.4 and 14.8±3.1 minutes, respetively (P<0.01); and at the same time, the central depressant effect became less marked. On combination with regitine (1 mg intraventricularly), the duration of loss of righting reflex was prolongted to 50.0+10 minutes (P<0.05) with the central depressant effect potentiated.Following intraventricular anisodine (0.4 mg), a gradual EEG change from low voltage rapid wave to high voltage slow wave was observed lasting for about 6 hours. Additional intravenous physostigmine 0.2 mg/kg, given 15 minutes after the administration of anisodine, produced a reappearance of low voltage rapid wave lasting for about 30 minutes, while the similar use of noradrenaline or adrenaline (150 μg intraventricularly) gave a trasient reappearance, lasting 3～4 minutes only.These results suggested that the central depressant effect of anisodine can be antagonized by physostigmine and adrenomimetics, while regitine is synergistic.