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 presence of the messenger ribonucleic acid (mRNA) for the dopamine D-1 and D-2 receptors and the prolactin receptor in meningioma tissue specimens and cell cultures derived from meningioma tissue. Dopamine D-1 receptor mRNA was present in a majority of female tissue specimens and in all male tissue specimens. D-2 receptor mRNA was detected in all specimens examined. Prolactin receptor mRNA was present in a little more than half of the female and male meningioma tumor specimens. The polymerase chain reaction products were directly sequenced to confirm the identity of these receptors in meningiomas and cell cultures. Ligand binding studies confirmed the presence of the dopamine D-1 receptor in meningioma tissue specimens. In contrast, receptor studies with the dopamine 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.