New central dopamine agonists

Recently, the importance of the dopamine receptor agonists has increased in the treatment of parkinsonism, different endocrinological diseases and cardiovascular illness. In the therapy some well known drugs, derivatives of ergot groups e.g. bromocriptine, lisuride and pergolide, have been found useful. In the Institute for Drug Research numerous semi-synthetic elymoclavine derivatives were synthesized during the past years, and the influence of these new compounds on both the central and peripheral dopamine transmission was examined. Among the different ergot derivatives compound GYKI-32 887 seemed to be the most effective dopamine agonist and it was selected for preclinical investigation. The endocrinological effects and the pre- and postsynaptic dopamine receptor stimulant activity of this new compound are summarized. GYKI-32 887 was more potent than bromocriptine as regards its inhibitory effect on prolactin secretion and antiparkinsonian efficacy. Besides the strong dopamine receptor stimulant action this new ergoline compound, contrary to bromocriptine, inhibits the convulsive action of bicucullin. It may be assumed that the GABA receptor agonistic effect of GYKI-32 887 would be also valuable in the treatment of various form of dyskinesias.