Antidopaminergic effects of leucine and genistein on shizophrenic rat models.

OBJECTIVE To evaluate the effect of leucine and genistein on the dopaminergic system in a rat model of schizophrenia. METHODS Behavioral effects of leucine and genistein on apomorphine induced stereotyped behavior, haloperidol induced catalepsy, foot shock induced aggression, and apomorphine induced locomotor activity were conducted. In each of these tests, the leucine (0.7g/kg p.o.) and genistein (30mg/kg i.p.) were administered 30 minutes before performing the test in rats. Each experiment has 6 groups of rats with 6 rats in each group. The current study was conducted between April 2011 and September 2011 at the Department of Pharmacology, St.Peters Institute of Pharmaceutical Sciences, Warangal, Andhra Pradesh, India. The results were expressed as mean +/- S.E.M. and the statistical analysis of data was carried out using one-way analysis of variance (ANOVA), followed by Bonferroni multiple comparison test. Probability level (P) less than 0.05 was considered statistically significant. RESULTS Leucine and genistein significantly (p<0.05) reduced the number of fights and increased latency to fights in foot shock-induced aggression; it also decreased apomorphine (5mg/kg, i.p.) induced stereotyped behavior and apomorphine induced (10mg/kg, s.c.) locomotor activity when compared with the positive control group. Pretreatment with leucine and genistein significantly (p<0.01, 55.5 +/- 5.898 minutes) potentiated the haloperidol induced catalepsy compared with the haloperidol treated group. CONCLUSION The individual administration of leucine and genistein had less anti dopaminergic activity when compared with their combined administration. These results suggest that leucine and genistein may have a potential clinical application in the management of psychiatric disorders.