Rui Yan-fang, Sun Zhao-hui, Gu Jia-ping, Shen Zhong-hua, He Xiang-ping, Xie Zuo-ping
Department of Biological Science and Biotechnology, State Key Laboratory of Biomembrane and Membrane Biotechnology, Tsinghua University, Beijing 100084, China.
Acta Pharmacol Sin. 2006 Jul;27(7):869-76. doi: 10.1111/j.1745-7254.2006.00387.x.
To investigate the changes in synchronized spontaneous Ca2+ oscillations induced by mitogen-activated protein kinase kinase (MEK) inhibitor PD98059 at different concentrations in cultured hippocampal network.
Hippocampal neurons in culture for 1-2 weeks were used for this study. Spontaneous synaptic activities of these hippocampal neurons were examined by Ca2+ imaging using calcium-sensitive dye. MEK inhibitor PD98059 (10, 30, and 60 micromol/L) and SB202474 (10 and 60 micromol/L), a negative control for mitogen-activated protein kinase (MAPK) cascade study, were applied to the cells under the microscope while imaging was taking place.
PD98059 at a lower concentration of 10 micromol/L had little effect on the Ca2+ oscillation. At the higher concentration of 30 micromol/L, 5 min after application of PD98059, the spike frequency was decreased to 25.38% +/-7.40% (mean+/-SEM, n=16, P<0.01 vs medium control) of that of the control period. At an even higher concentration of 60 micromol/L, 5 min after application of PD98059, the spike frequency was decreased to 14.53%+/-5.34% (mean+/-SEM, n=16, P< 0.01 vs medium control) of that of the control period. The spike amplitude underwent a corresponding decrease. However, the negative control SB202474 at concentrations of 10 and 60 micromol/L had little inhibition effect on the Ca2+ oscillation.
These results indicate that PD98059 inhibits synchronized spontaneous Ca2+ oscillation through inhibition of MEK, which hints that the MAPK cascade is required to maintain synchronized spontaneous Ca2+ oscillation.
