Pharmacological studies on drug interaction. V. Effect of adenyl compounds on L-dopa (author's transl)

Abstract

Effect of adenosine 2'-monophosphate (2'AMP) in combination with L-dopa on spontaneous motor activity and brain monoamine levels in mice and on spontaneous unit discharges of substantia nigra in the cat was investigated, and the following results were obtained. 1) spontaneous motor activity in mice treated with 2'AMP (50 mg/kg, s.c.) plus L-dopa increased significantly compared with that in mice treated with L-dopa alone. No enhanced action was observed by the combined use of L-dopa in mice treated with adenosine 3'-monophosphate or with adenosine. 2) Compared with mice treated with L-dopa alone, in mice treated with 2'AMP plus L-dopa, no significant difference was detected in the noradrenaline, dopamine, and serotonin levels in the whole brain. 3) There was no change in unit discharges of substantia nigra in the cat by treatment with L-dopa, but they increased significantly by using 2'AMP plus L-dopa. Consequently, it was assumed that enhaced activity by 2'AMP plus L-dopa was associated with supersensitivity in the central catecholamine recepter.