Effects of befloxatone, a new potent reversible MAO-A inhibitor, on cortex and striatum monoamines in freely moving rats.

Single administration of befloxatone (0.75 mg/kg, i.p.) in the rat increased extracellular levels of DA (+300%) in striatum. In frontal cortex, befloxatone (0.75 mg/kg, i.p.) and nialamide (100 mg/kg, i.p.) increased NA by +100% but did not modify 5HT, whereas pargyline (100 mg/kg i.p.) increased extracellular NA and 5HT by 400 and 600%, respectively. At these doses, befloxatone inhibited totally and selectively MAO-A, pargyline inhibited totally MAO-A and MAO-B. Increases of tissue and extracellular concentrations of NA and 5HT were highest after Pargyline suggesting that both monoamines may be metabolized by MAO-A and MAO-B. Befloxatone and nialamide potentiated the effects of idazoxan (20 mg/kg, i.p.) on extracellular NA in frontal cortex, which increased from 350% to 2,000 and 1,500% respectively. These results suggest that alpha 2-adrenoceptors play a major role in the regulation of extracellular NA in frontal cortex.