RESUMO
Objective To study the effect of N-Methyl-D-asparticacid ( NMDA ) on the intracellular free calcium concentration ( [ Ca2+] i ) in primary cultured rat calvaria osteoblasts. Methods A calcium imaging technique was applied to observe [ Ca2+] i changes in primary cultured rat calvaria osteoblasts after stimulating by NMDA with various concentrations or pretreated with NMDA receptor noncompetitive antagonism MK801 ( Dizocilpin) . Results Different concentrations of NMDA caused [ Ca2+] i increases in varying degrees and by different ways. NMDA could evoke transient increase and secondary change in [ Ca2+] i including calcium oscillation or steady increase. MK801 inhibited NMDA-induced [ Ca2+] i increase in varying degrees. Conclusion These results indicated that there are abundant functional NMDA receptors expressed in primary cultured rat calvaria osteoblasts, showing different forms and varying degrees of [ Ca2+] i increases in response to different concentrations of NMDA. The characters of the blocking effect of MK801 to NMDA-induced [ Ca2+] i increasing, indicated that the NMDA receptors expressed in primary cultured rat calvaria osteoblasts differ in channel properties from those in central nervous system.