Brain GABA level

Effect of nicotine on brain GABA levels in depressed rats. The present study was planned: to study effect of nicotine on brain GABA levels in depressed rats. to compare the effect of nicotine and imipramine on brain GABA levels. Isolation induced hyperactivity model was used to induce depression in rats. Five groups of 10 rats each were taken. Vehicle (D/W) treated rats before and after isolation were considered as baseline reading. Compared results of depression induced animal with results of animal without depression. Following drug treatments were administered: Rats from natural habitat was considered as before isolation. This group was used for normal GABA levels in rat brain. Vehicle (D/W) (1ml/kg) and imipramine (10mg/kg) were administered intraperitoneally. Nicotine was administered in a dose of 0.4mg/kg and 0.2mg kg by subcutaneous or inhalational route respectively. Brain GABA levels were estimated by fluorimetric method. In this model of depression, vehicle treated rats after isolation significantly reduced brain GABA levels as compared to vehicle before isolation.  Results of imipramine treated rats after isolation showing significantly increased in brain GABA levels as compared to vehicle treated rats after isolation. Nicotine administered by inhalational route showed increase in brain GABA levels as compared to vehicle treated rats after isolation. Nicotine administered subcutaneously increased brain GABA levels as compared to vehicle treated rats after isolation. Imipramine and nicotine (inhalation) showed comparable results with  normal GABA level i.e. before isolation rats. GABA level reduced in depressed rats. Imipramine, nicotine(inhalation) and nicotine(sc) increased  brain GABA level in depressed rats.