GROWTH OF CULTURED HUMAN CEREBRAL MENINGIOMAS IS INHIBITED BY DOPAM1NERGIC AGENTS. PRESENCE OF HIGH AFFINITY DOPAMINB-D1 RECEPTORS

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Abstract
We have found that .mu.M concentrations of the dopamine agonist bromocriptine significantly decrease the proliferation rate of human meningioma cells in culture (25 - 56% inhibition). This effect was also seen with direct application of dopamine, as well as the dopamine-D1 agonist (+)-SKF-38393 (both applied in .mu.M concentrations) to meningioma cell cultures. Receptor studies with the dopamine-D1 ligand (125I)SCH-23982 (dopamine-D1 antagonist) indicated that dopamine-D1 binding sites were present in the membranes of meningioma tissue. The mean dissociation constant (Kd) was 325 (.+-.74.5 SEM) pM and the receptor density (Bmax) was 25.4 (.+-.1.5 SEM) fmol/mg pellet protein in 5 human meningiomas. The pharmacological specifity was proven by (+)-SKF-38393, (.+-.)-SKF-83566 or (+)-butaclamol and their inactive isomers (-)-SKF-38393 and (-)-butaclamol in a 1000 fold excess. These results provide evidence that human meningiomas possess high affinity dopamine-D1 receptors and that dopamine agonists have an antiproliferative effect on these tumors in culture. We conclude that the proliferation of cerebral meningiomas may be under dopaminergic control and that dopamine agonists may have a role in the medical treatment of patients with meningiomas.