Effects of melatonin on the voltage-gated delayed rectifier potassium channels of cultured hippocampal neurons of new-born rats
Yin, Y.-q.; Luo, A.-l.; Guo, X.-y.; Zheng, J.-q.; Ren, H.-z.; Ye, T.-h.; Huang, Y.-g.
Zhonghua Yi Xue Za Zhi 88(11): 769-772
2008
ISSN/ISBN: 0376-2491 PMID: 18683687 Document Number: 619569
To investigate the effects of melatonin on voltage-gated delayed rectifier potassium channels. Hippocampus neurons were obtained from newborn Wistar rat and cultured. Primary cultured for 7 to 12 days of new-born Wistar rat were selected as objectives. Patch clamp whole-cell recording technique was used on the hippocampus neurons cultured for 7 to 12 day. to record the delayed rectifier potassium current to analyze the basic electrophysiological characteristics. The effects of melatonin of the concentrations of 1 nmol/L, 10 nmol/L, 100 nmol/L, 1 mol/L, 10 mol/L, 100 mol/L, and 1 mmol/L on the amplitudes and kinetics of delayed rectifier potassium currents were investigated. With different voltage protocols and specific blockers of potassium channel (4-AP and TEA) a delayed rectifier potassium current that activated and inactivated slowly and had the outward rectifying characteristics (Ik) from the outward potassium currents in cultured new-born hippocampus neurons was separated. The effect of melatonin on the delayed rectifier channel was rapid, reversible and voltage-dependent Melatonin had no effect on the kinetic characteristics of the I -V curve. Melatonin increased the potassium current concentration-dependently. 1 - 100 nmol/L melatonin increased the amplitude of potassium current gradually; the effects of 1 - 100 micromol/L melatonin on the potassium current increased concentration-dependently, while the action of 1 mmol/L melatonin decreased. Melatonin reversibly increases the rectifier delayed potassium currents of the cultured hippocampus neurons of new-born rat. This may be involved in some aspects of physiological and pathological significance of potassium currents.