Modification of cerebral cortical noradrenaline release by chronic inhibition of MAO-A

Chronic treatment of rats with clorgyline (1 mg/kg i.p. daily for 21 days) caused a highly significant increase in the concentration of noradrenaline in microdialysate from the frontal cortex of the awake animal. Acute (one injection, 2 mg/kg) or subacute (1 mg/kg daily for 3 days) treatment did not lead to a significant increase in microdialysate noradrenaline. Concentrations of deaminated metabolites (DPHG, MHPG, DOPAC) in the microdialysate decreased with time of treatment, reaching a minimum after 21 days.