Inhibition by venlafaxine of the increase in norepinephrine output in rat prefrontal cortex elicited by acute stress or by the anxiogenic drug FG 7142.

Venlafaxine is an antidepressant drug that inhibits the reuptake of serotonin and norepinephrine with different efficacies. The effects of repeated administration of this drug on the increase in the extracellular concentration of norepinephrine in the prefrontal cortex, induced by stress or by the anxiogenic drug FG 7142, were studied in freely moving rats. Exposure to foot-shock stress induced a marked increase (+120%) in the extracellular norepinephrine concentration in the prefrontal cortex of control rats.

Depletion of cortical allopregnanolone potentiates stress-induced increase in cortical dopamine output.

In freely moving rats finasteride markedly reduced the cortical content of allopregnanolone. This treatment significantly prolonged the increase in the extracellular concentration of dopamine in the prefrontal cortex induced by foot shock. Moreover, finasteride enhanced both maximal increase of dopamine and its duration elicited by a single injection of the anxiogenic drug FG 7142.

Chronic treatment with imipramine or mirtazapine antagonizes stress- and FG7142-induced increase in cortical norepinephrine output in freely moving rats.

The effect of repeated administration of imipramine or mirtazapine, two antidepressant drugs with different mechanisms of action, was studied on the stress-induced increase in the extracellular concentration of norepinephrine in the prefrontal cortex of freely moving rats. Exposure to footshock in control rats induced a marked increase in extracellular norepinephrine concentrations in the prefrontal cortex (+120%). Long-term administration with imipramine or mirtazapine (10 mg/kg, i.