Abstract
Our current study aims to explore the interaction of melatonin (MEL) with the monoaminergic system on the pathophysiology of affective disorders in Wistar rats. We mention here that, the role of monoaminergic transmission in the pathophysiology of affective disorders in humans is demonstrated in most recent reports. In this sense, our current work aims to explore the effect of melatonin (MEL) with or without imipramine (IMP) on levels of depression and anxiety in Wistar rats and would determine the role of MEL in modulating serotonin, noradrenaline and dopamine neurotransmission. From this point, twenty-four female Wister rats were divided into 4 groups of 6 animals and received subcutaneously during 4 weeks different doses of MEL (4 mg/kg), IMP (2 mg/kg) or MEL (4 mg/kg) + IMP (2 mg/kg). Behavioral performance especially anxiety and depression is measured in the open field (OFT), elevated plus maze (EPM) and forced swim test (FST). The anxiety-like and antidepressant-like effects were observed with MEL at 4 mg/Kg and IMP at 2 mg/Kg but the potentiating effect was more observed with the two combined molecules (MEL and IMP), since locomotors activity assessed by the OFT and EPM was not affected. These effects suggest that psychopharmacological actions of MEL are due, at least in part, to its ability to potentiate the central monoaminergic transmitter effects.
Highlights
There is a clear relationship between the affective disorders and brain levels of monoaminergic neurotransmitters serotonin (5-HT), noradrenalin (NA) and dopamine (DA)
Our current work aims to explore the effect of melatonin (MEL) with or without imipramine (IMP) on levels of depression and anxiety in Wistar rats and would determine the role of MEL in modulating serotonin, noradrenaline and dopamine neurotransmission
We showed in this study that chronic injection of MEL induced an anxiolytic effect in both OFT and elevated plus maze (EPM), since the animals of control group are less mobile in the environment of both anxiety paradigms
Summary
There is a clear relationship between the affective disorders and brain levels of monoaminergic neurotransmitters serotonin (5-HT), noradrenalin (NA) and dopamine (DA). The fact that some antidepressants that increase brain neurotransmitter 5-HT-ergic relieve anxiety symptoms suggests that anxiety disorders share common mechanisms etiopathological with depression [1]. The treatment of affective disorders by antidepressants, especially tricyclic antidepressants (TCA) is effected by activation of 5HT-ergic, by inhibiting the reuptake of 5-HT, inhibiting its degradation by MAO, or indirectly by blocking the α2-receptors NA-ergiques [2]. Among these antidepressants, IMP is known to block neuronal reuptake of NA and 5-HT. Its action extends to other neurotransmitters by inhibiting the reuptake of DA, cholinergic muscarinic receptors, histamine H1 receptors and α1-NA-ergic receptors
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
