[Inhibitory monoamine oxidases of the new generation]

This review deals with the new generation of selective and partly reversible monoamine oxidase (MAO) inhibitors. In contrast to the non selective inhibitors, used in the year 1957-1970, the selective inhibitors bind to and block only one of the two isoenzymes, MAO-A or MAO-B. The MAO-A inhibitors and part of the MAO-B inhibitors differ also from the classic drugs by their reversibility. The inhibition of MAO-A cause the rise of norepinephrine, dopamine and serotonin in the synaptic cleft, of MAO-B only of dopamine. The new inhibitors diminish also to some extent the reuptake of monoamines. The molecular action mechanism of the new drug generation is the same as in the non-selective drugs: increase of monoamines, near to the receptor, leads, after a number of intermediate steps, to activation of functional proteins in the cell. The selective block of one of the isoenzymes does not stop the metabolism of tyramine (from cheese, red wine), because this toxic compound is metabolised by both isoenzymes. The control of therapy with MAO-A inhibitors is easier, because of their reversibility. Selective inhibitors of MAO have found a secure place in therapy of depression (inh. of MAO-A, esp. Moclobemide) and Parkinson's disease (inh. of MAO-B, at this time mainly selegiline). Discussed is possible use of selective MAO-inhibitors for achieving an increase in cognitive function and protections of neurone cells from biochemical lesions.