|
The Goldman–Hodgkin–Katz voltage equation, more commonly known as the Goldman equation, is used in cell membrane physiology to determine the reversal potential across a cell's membrane, taking into account all of the ions that are permeant through that membrane. The discoverers of this are David E. Goldman of Columbia University, and the English Nobel laureates Alan Lloyd Hodgkin and Bernard Katz. ==Equation for monovalent ions== The GHK voltage equation for monovalent positive ionic species and negative: : This results in the following if we consider a membrane separating two -solutions: : It is "Nernst-like" but has a term for each permeant ion: : * = The membrane potential (in volts, equivalent to joules per coulomb) * = the permeability for that ion (in meters per second) * = the extracellular concentration of that ion (in moles per cubic meter, to match the other SI units) * = the intracellular concentration of that ion (in moles per cubic meter) * = The ideal gas constant (joules per kelvin per mole) * = The temperature in kelvins * = Faraday's constant (coulombs per mole) The first term, before the parentheses, can be reduced to 61.5 mV for calculations at human body temperature (37 °C) : Note that the ionic charge determines the sign of the membrane potential contribution. Note also that during an action potential, although the membrane potential changes about 100mV, the concentrations of ions inside and outside the cell do not change significantly. They are always very close to their respective concentrations when the membrane is at their resting potential. 抄文引用元・出典: フリー百科事典『 ウィキペディア(Wikipedia)』 ■ウィキペディアで「Goldman equation」の詳細全文を読む スポンサード リンク
|