AIM: To investigate the effects of intracellular free calcium ([Ca2+]i) from different resources on the proliferation mediated by mitogen activated protein kinase (MAPK) in vascular smooth muscle cells (VSMCs). METHODS: Cultured VSMCs were used in all experiments. Calcium influx was stimulated by angiotension Ⅱ(Ang Ⅱ). The release of intracellular calcium stores was induced by inositol trisphosphate (IP3) and ryanodine (RY). MAPK activity was measured by [γ-32P]-ATP incorporation MAPK protein expression by western blot, VSMCs proliferation by [3H]-Leucine ([3H]-Leu) and [3H]-Thymidine ([3H]-TdR) incorporation. RESULTS: Compared to the control VSMCs, Ang Ⅱ, IP3 and RY significantly increased [Ca2+]i concentration activity of MAPK and its protein content in VSMCs. The promotion of [3H]-Leu and [3H]-TdR incorporation in VSMCs was also observed (P<0.01). CONCLUSION: The study indicated that calcium activator-induced increase in the activity and protein content of MAPK was involved in the proliferation of VSMCs, which was closely related to the [Ca2+]i concentration but independent to its origin. 相似文献