Biochemical effects of ethyl apovincaminate.

Some cerebrobiochemical effects of a new cerebrovasodilatory agent, ethyl apovincaminate (RGH-4405, Cavinton) have been studied. Changes of biogenic amines, 5-hydroxyindole acetic acid (5-HIAA) levels, serotonin (5-HT) turnover rate, furthermore effect on 3',5'-cyclic nucleotide phosphodiesterase (PDE; E.C.3.1.4.c) activity, isolated from different tissues, were determined. Lasting increase of cerebral 5-HIAA level was observed after treatment with the compound, 5-HT levels were transitorily enhanced 2 h following i.p. treatment. At later periods (4-6h) after treatment catecholamine levels were significantly raised. 5-HT turnover was practically uninfluenced by the compound. Activities of PDE preparations isolated from cerebral tissues were markedly inhibited. Various hypotheses are suggested in order to explain the biochemical mechanism of action of the compound.