Dopamine receptor expression on primary osteoblasts and bone marrow mesenchymal stem cells of rats

Bone metabolism and the underlying mechanisms are of great interest, particularly in the context of clinical bone tissue repair and tissue engineering. Neurotransmitters play an important role in bone metabolism. Dopamine is an important neurotransmitter with several critical functions in the central nervous system, and is likely involved in bone metabolism. However, the expression of dopamine receptors in the bone marrow stem cells and osteoblasts has not been extensively studied to date. In this study, we determined whether two types of dopamine receptors, dopamine receptor 1 (D1R) and dopamine receptor 2 (D2R), were expressed on osteoblasts and bone marrow mesenchymal stem cells (BMMSCs) in rats, by using polymerase chain reaction, western blot, and immunofluorescence. Immunohistochemistry was used to confirm the expression of D1R and D2R in the mandible of the rats. The results showed that D1R and D2R are expressed on rat osteoblasts and BMMSCs. Both receptors were distributed in the dental pulp, periodontal tissue, and bone tissue. Our results suggested that dopamine could affect the biological behavior of osteoblasts and BMMSCs by directly binding to its receptors. D1R and D2R could therefore directly modulate bone metabolism.