DOPAMINE D-1, DOPAMINE D-2, AND PROLACTIN RECEPTOR MESSENGER-RIBONUCLEIC-ACID EXPRESSION BY THE POLYMERASE CHAIN-REACTION IN HUMAN MENINGIOMAS

PREVIOUS STUDIES HAVE suggested the presence of high-affinity dopamine D-1 receptors and prolactin receptors in human cerebral meningiomas. In this study, using the polymerase chain reaction, we report the pres ence of the messenger ribonucleic acid (mRNA) for the dopamine D-1 and D-2 receptors and the prolactin receptor in meningioma tissue specime ns and cell cultures derived from meningioma tissue. Dopamine D-1 rece ptor mRNA was present in a majority of female tissue specimens and in all male tissue specimens. D-2 receptor mRNA was detected in all speci mens examined. Prolactin receptor mRNA was present in a little more th an half of the female and male meningioma tumor specimens. The polymer ase chain reaction products were directly sequenced to confirm the ide ntity of these receptors in meningiomas and cell cultures. Ligand bind ing studies confirmed the presence of the dopamine D-1 receptor in men ingioma tissue specimens. In contrast, receptor studies with the dopam ine D-2 ligand [I-125]4-iodospiperone failed to detect D-2 binding in meningioma membrane preparations. These results suggest the existence of active dopamine D-2 receptors in cerebral meningiomas.