Effect of venlafaxine and nicotine on the level of neurotransmitters and their metabolites in rat brains.

Nicotine (NIC) and venlafaxine (VEN) have been proved to exert antidepressant activity in both human and animals. The effect of antidepressant doses of NIC and VEN (our previous results) on noradrenergic (NA), dopaminergic (DA), serotoninergic (5-HT) neurotransmitters and their metabolites: DOPAC, HVA and 5-HIAA in rats' hippocampus in freely moving rats were determined by microdialysis technique and HPLC method. Both drugs release 5-HT and NA, but VEN to a greater degree. DA level was affected only by VEN, however NIC extended the response of the DA system on VEN's effect. Combined administration of drugs caused the greatest changes in the 5-HT system. Both drugs contributed to reduction in neurotransmitter biotransformation.