THE INFLUENCE OF THE ANTIDEPRESSANT PIRLINDOLE AND ITS DEHYDRO-DERIVATIVE ON THE ACTIVITY OF MONOAMINE-OXIDASE-A AND GABA(A) RECEPTOR-BINDING

The influence of pirlindole and dehydro-pirlindole on GABA(A) receptor binding and MAO-A activity was investigated in vitro. Inhibition of r at brain and human placenta MAO-A by both compounds was much more pote nt (with IC50 range 0.3-0.005 mu M) than that of GABA(A) receptors. Pi rlindole was inactive as a GABA antagonist. Dehydro-pirlindole exhibit ed selective blockade of GABA-A receptors with EC50 12 mu M. Effects o f both compounds on MAO-A activity were partially reversible. Data obt ained suggest that in contrast to pirlindole dehydro-pirlindole may ac t not only as a MAO-A inhibitor but also as a potent GABA(A) receptor blocker.