Hyperpolarization-activated cation currents and nervous system disease

• 作 者: HeZ;YouY;
• 机 构: Department of Pharmacology,Medical Science College,China Three Gorges university Yichang,Hubei China
• 出 处: The 3rd Ion Channel Conference: Ion channels-Structure, Func
• 发表日期: 2011年期

　　_Hyperpolarization-activated cation currents (Ih) have puzzled physiologists since their initial discovery in heart over 30 years ago.Unlike most voltage-dependent ion channels, these channels are opened by hyperpolarization of the membrane rather than by depolarization and are activated slowly.They conduct both K+ and Na+ ions, with a threefold greater permeability to K+, yielding a reversal potential of-30 to-40 mv that is positive to the neuronal resting membrane potential.Ih is regulated by cAMP and does not require protein phosphorylation.These channels are proposed to play a fundamental role in determining the neuronal resting membrane potential, shaping the autonomous rhythmic activity of neurons, dendritic integration, synaptic transmission, synaptic plasticity, neurotransmitter release and the periodicity of network oscillations.With the development of molecular biology, a family of four mammalian genes that encode the hyperpolarization-activated, cation nonselective channels, HCN 1-4, are identified.HCN are expressed widely in smooth and in many different peripheral and central neurons.