[Electrophysiological correspondence between Kv4.2 current and transient outward potassium current in the cultured rat hippocampal neuron].
The present study was carried out to determine the functional properties of Kv4.2 expressed in mammalian cells in comparison with native transient potassium outward current (I(A)) in the hippocampal neurons. Transient transfection, cell culture and whole cell voltage clamp techniques were used. The results showed that I(A) in cultured rat hippocampal neurons and Kv4.2 expressed in HEK293 cells both displayed "A"-type current properties. The activation curves of I(A) and Kv4.2 were better fitted by simple Boltzmann function with V(1/2)   10.0+/-3.3 mV, k 13.9+/-2.6 mV for I(A) and V1/2 -9.7+/-4.1 mV, k 15.8+/-5.7 mV for Kv4.2, respectively. The steady-state inactivation curves of I(A) had a midpoint of -93.0+/-11.4 mV and a slope of 9.0+/-1.5 mV. The voltage-dependence of inactivation for Kv4.2 exhibited midpoint and slope values of -59.4+/-12.2 mV and 8.0+/-3.1 mV, respectively. The time constants (tau) of recovery from inactivation of I(A) and Kv4.2 were 27.9+/-14.1 ms and 172.8+/-10.0 ms, respectively. These results suggest that Kv4.2 is probably a major isoform contributing to I(A) in hippocampus neurons.
Jin
Hong-Wei
HW
Institute of Materia Medica, Chinese Academy of Medical Science Peking Union Medical College, Beijing 100050.
Zhang
Wei
W
Qu
Lin-Tao
LT
Wang
Xiao-Liang
XL
D000818:Animals; D000831:Animals, Newborn; D002478:Cells, Cultured; D005260:Female; D018014:Gene Transfer Techniques; D006624:Hippocampus / Q000378:metabolism / Q000502:physiology*; D017136:Ion Transport; D008297:Male; D009474:Neurons / Q000378:metabolism / Q000502:physiology; D018408:Patch-Clamp Techniques; D026902:Potassium Channel Blockers; D015221:Potassium Channels / Q000235:genetics* / Q000502:physiology; D024642:Potassium Channels, Voltage-Gated; D051381:Rats; D017208:Rats, Wistar; D051672:Shal Potassium Channels
C497023:Kcnd3 protein, rat; D026902:Potassium Channel Blockers; D015221:Potassium Channels; D024642:Potassium Channels, Voltage-Gated; D051672:Shal Potassium Channels