Modulating Role of Mirtazapine on Concentrations of both Glutamate and GABA in Nucleus Accumbens of Chronic Mild Stressed Albino Rats

Mirtazapine {1,2,3,4,10,14b-hexa-hydro-2-meth-ylpyrazino [2,1a] pyrido [2,3-c]benzazepin} is a tetracyclic compound with antidepressant activity in human [1]. Mirtazapine has a unique mechanism of action, different from that of the classical tricyclic antidepressants, the serotonin selective reuptake inhibitors and monoamine oxidase inhibitors, and could be described as a noradrenergic and specific serotonergic antidepressant, abbreviated as NaSSA [2]. The pharmacological profile of mirtazapine is characterized by potent presynaptic 2-adrenergic antagonistic activity, 5-HT1 agonistic activity, and potent 5-HT2 and 5-HT3 antagonistic activities, as well as by a potent H1 antagonistic activity. The blockade of presynaptic _2-adrenergic receptors is considered as a possible mechanism for antidepressant activity of mirtazapine [3].