Noise analysis of an ion channel in the cardiac myocyte--study based on a Markov model.
Mechanical contraction of a cardiac muscle cell is related to the electric activation of the plasma membrane. As in the neuron cell, inflow of the Na(+) ions across the cell membrane causes electric activation with amplitude of about 100 mV. However, differently from the nerve cell, the action potential lasts a few hundred milliseconds before repolarization. Moreover, several types of K(+) channel such as the classical inward rectifier K(+) channel, the voltage dependent channel and others are responsible for the formation of the action potential. The mechanism of opening and closing the K(+) channels is not thoroughly elucidated. In the present paper, a four state Markov model with one open and three closed states is studied to obtain open and close probabilities of the gates constituting a specific ionic channel. The probability density functions of durations of opening and closing of the channel are also discussed.
Sato
Shunsuke
S
Aino University, 4-5-4, Higashi-Ohda, Ibaraki, Osaka 567-0012, Japan. s-sato@pt-u.aino.ac.jp
D000465:Algorithms; D000818:Animals; D004594:Electrophysiology; D006801:Humans; D015640:Ion Channel Gating / Q000502:physiology*; D007700:Kinetics; D008390:Markov Chains; D008564:Membrane Potentials / Q000502:physiology; D008954:Models, Biological; D032383:Myocytes, Cardiac / Q000502:physiology*; D011188:Potassium / Q000378:metabolism; D024642:Potassium Channels, Voltage-Gated / Q000502:physiology*; D011336:Probability; D015222:Sodium Channels / Q000502:physiology
D024642:Potassium Channels, Voltage-Gated; D015222:Sodium Channels; D011188:Potassium