Electrophysiology of hyperpolarization-activated cyclic nucleotide-gated cation channel 2 and hyperpolarization-activated cyclic nucleotide-gated cation channel 4 expressed in HEK293 cells
Li, C.; Guo, J-hong.; Li, J-wen.; Liu, Y-wei.; Hao, X-mei.; Zhang, P.; Wang, S-qiang.
Chinese Medical Journal 120(22): 2039-2041
2007
ISSN/ISBN: 0366-6999 PMID: 18067793 Document Number: 609843
The action potential of pacemaker cells in the sino-atrial node forms the automatic rhythm of the heart. The automatic depolarization in phase 4 is the basis of the automaticity in pacemaker cells. Many currents are included in phase 4, such as calcium current,(1) TTX-sensitive sodium current,(2) sustained inward current (I-si),(3) decay of delayed rectifier potassium current,(4) etc. Funny current (I-f) has long been recognized as important in this phase and is activated at hyperpolarized potentials during cell diastole and in turn activates other currents to form automatic depolarization.(5) It is controlled by voltage and cAMP, an intracellular messenger, so the auto no-mic nerve can modulate this current by increasing or decreasing intracellular cAMP Since a gene family termed hyperpolarization-activated cyclic nucleotidegated cation channel (HCN) was discovered to encode this channel, there are few domestic articles concerning the electrophysiology of the different types of this channel.(6) The aim of this article is to describe the electrophysiological properties of human HCN2 and HCN4 channels expressed in HEK293 cells.