Question

Choose one electrophysiological method and use the details of one ion channel we did not discuss (choose from HCN, Cl-, or TRP ion channels) to explain how it is performed.

Answer 1

Hyperpolarization activated and cyclic nucleotide gated (HCN) channels were first reported in heart cells and are recently known to be involved in a variety of neural functions in healthy and diseased brains. HCN channels generate inward cuurent when the membrane potential is hyperpolarized. Voltage dependence of HCN channel is regulated by itracellular signaling cascade, which contain cyclic AMP, PIP2, and TRIP8b. In addition, voltage gated potassium channels have a strong influence on HCN channel activity. HCN channel currents, priviously called funny currents, can have a wide range of function that are determined by a delicate balance of modulatory factors.

HCN channels are involved in many kinds of functions that range from cellular to behaviour levels, initiation of neuropathic pain. HCN Channels can work both excitatory and inhibitory, and these effect can be altered by pharmacologicall modulation, HCN channels are one of the promising pharmacological targets in treating disease of the brain.

Dendritic HCN channels normalize synaptic input in the cortical and hippocampal neurons. Current density of HCN channels increases along with the distance from the soma in hippocampal and neocortical pyramidal neurons.

Activated HCN channel conductance reduces the membrane resistance. This reduction suppresses the impact of synaptic inputs on membrane potential. As HCN channels activate more, the amplitude and kinetic of postsynaptic potential become smaller and shorter.