Publication:

Evaluation of anti-psychotic effect of nimodipine using methylphenidate as a model to induce psychosis in albino mice

Background Schizophrenia is a functional psychotic disorder currently treated by typical and atypical antipsychotic drugs. A large group of patients remain resistant to therapy. Nimodipine has been found effective for treating resistant bipolar mood disorder which is linked genetically with schizophrenia and has a high overlap of neurotransmitters in the etiopathology. Previous studies to evaluate nimodipine’s antipsychotic activity have shown inconsistent results. Methylphenidate, a CNS stimulant like amphetamine, has been shown to induce stereotypy in animals and can be proposed as an alternative model for psychosis.

Methods Methylphenidate 5 mg/kg was given intraperitoneally to induce psychosis in swiss albino mice (n=6). Nimodipine was given alone in doses of 2.5 and 5 mg/kg by i.p route and in combination with haloperidol 0.1 mg/kg and effects were compared with haloperidol 0.2mg/kg. Activity of nimodipine was also assessed on the haloperidol induced catalepsy test. Statistical analysis was done with ANOVA followed by Bonferroni’s test using SPSS v. 20.0.

Results Methylphenidate successfully induced characteristic stereotypy behaviour in mice similar to amphetamine. Both nimodipine 5 mg/kg and haloperidol 0.2 mg/kg showed significant reduction in stereotypy behaviour with no statistical difference between the two; result with nimodipine were only slightly inferior to haloperidol. Nimodipine 5 mg/kg with haloperidol 0.1 mg/kg showed significantly better activity than haloperidol in standard dose of 0.2 mg/kg. Nimodipine did not show significant activity on the haloperidol induced catalepsy test.

Conclusions Methylphenidate has potential to be used as an alternative model for inducing psychosis in animals and nimodipine shows promising results for use as adjuvant antipsychotic drug.