ABSTRACT
Background: Schizophrenia as a psychotic disorder is currently treated by various antipsychotic drugs. A large group of patients still remain resistant to the treatment and present in the form of residual cognitive deficits. Donepezil has been advocated at various conferences and seminars for using it in schizophrenia patients. Donepezil is currently approved drug for Alzheimer's disease to improve cognition. Hence, we have tried to assess its role for psychotic models induced by methylphenidate in mice.Methods: Methylphenidate 5 mg/kg was given by intraperitoneal (i.p) route to induce psychosis in Swiss albino mice (n=6). Donepezil was given alone in a dose of 1 mg/kg and in combination with low dose haloperidol 0.1 mg/kg and groups were compared with haloperidol 0.2 mg/kg. Activity of donepezil was also assessed on the haloperidol induced catalepsy test. Statistical analysis was done with ANOVA followed by Bonferroni抯 test.Results: Methylphenidate successfully induced characteristic stereotypy behaviour in mice similar to amphetamine. Both donepezil 1 mg/kg and haloperidol 0.2 mg/kg showed significant reduction in stereotypy behaviour and there was no statistically significant difference between the two (p<0.05). Effects with donepezil were only slightly inferior to standard while it抯 combination (1 mg/kg with haloperidol 0.1 mg/kg) showed comparable results with the standard haloperidol. Donepezil had only marginally enhanced potential to induce catatonia which was statistically insignificant (p>0.05).Conclusions: Methylphenidate can be used successfully to induce psychosis in animals and donepezil may be a promising and potentially useful drug as add on therapy to routine antipsychotics.
ABSTRACT
Background: Cinnamon is one of the best known spices used as an herbal medicine. Cinnamaldehyde (CNM) the volatile oil, which was present in the essential oil of the bark, is the important constituents of cinnamon. Cinnamon has been investigated for its various effects like peptic ulcer protection, antioxidant property, inhibition of tau aggregation, anti-inflammatory activity, effect on cardiovascular system, anti-nociceptive activity, hepato-protective effects, hypolipidemic and antidiabetic activites. The present study was aimed to evaluate the anxiolytic effect of CNM per se and its interaction with diazepam in swiss albino mice.Methods: Anxiolytic activity was evaluated by elevated plus maze method. A group of 36 healthy mice of either sex weighing 20-30 grams were divided at random into six groups (n=6). CNM and diazepam were dissolved in tween twenty 20% to maintain uniformity of the solvent and given orally. Group I was given twenty 20% (10 ml/kg, p.o.), group II diazepam (0.5 mg/kg, p.o.), group III diazepam (1 mg/kg, p.o.), group IV cinnamaldehyde (100 mg/kg, p.o.), group V cinnamaldehyde (200 mg/kg, p.o.), group VI cinnamaldehyde and diazepam (100 mg/kg and 0.5 mg/kg, p.o.).Results: Cinnamaldehyde per se showed no anxiolytic effect at any dose (p<0.05). The standard drug diazepam has shown significant anxiolytic activity on elevated plus maze. Whereas combination of diazepam 0.5 mg/kg and cinnamaldehyde 100 mg/kg showed significant increase in the time spent in open arms as compared to all groups (p<0.05).Conclusions: CNM per se did not show any effect on anxiety but enhanced the action of diazepam when co-administered.