Effect of Wrightia tinctoria on the brain monoamines and metabolites in rats

The effect of acute administration of Wrightia tinctoria (Wt) (leaves) meth anolic extractives, constituting indigotin (HPTLC, relative abundance 21.97 (%), indirubin (27. 13 %), tryptanthrin (21 %), isatin (2.70 %) and rutin (14.24 %), was studied on the rat brain concentrations of monoamines and th eir metabolites in five different brain regions, viz. hypothalamus, hippoca mpus, striatum, pens medulla and frontal cortex. Wt extract was administere d at the doses of 25 and 50 mg/kg, i.p. and the brain monoamines were assay ed after 30 minutes of the treatment. Wt treatment significantly and dose d ependently decreased the levels of serotonin (5-HT), its metabolite 5-hydro xy indole acetic acid (5-HIAA) and their turnover in all the brain regions assayed. On the other hand, Wt treatment significantly and dose dependently augmented the levels of norepinephrine (NE), its metabolite methyl hydroxy phenyl glycol (MHPG) and also the turnover in all the brain regions studie d. Similarly, the levels of dopamine (DA) was also significantly augmented in the hypothalamus, striatum and frontal cortex. Likewise, the levels of d ihydroxy phenyl acetic acid (DOPAC), a metabolite of DA, was also increased in hypothalamus and frontal cortex. However, the treatment produced a sign ificant decrease in the DOPAC in striatum. This differential modulation of the neurotransmitters and their metabolites can explain the behavioural eff ects of Wt, namely anxiolytic and antidepressant effects.