| 摘要 |
Apparatus to measure the ion flows, at a single cell, having a micro measurement chamber (1) with a shape and dimensions to match the cell (4) under study, and the wall acts as a Ag/AgCl reference diode, is new. The ion flow measurement is through a constant chloride ion concentration of the extra-cellular solution (2) in the chamber, using a patch pipette (3) against the reference diode wall. Apparatus to measure the ion flows in a single cell having a micro measurement chamber, with a volume capacity twice the size of the volume of the cell to be measured, is new. An AgCl layer is deposited on the silver chamber wall before measurement. The voltage is determined iteratively before each patch clamp measurement, to maintain the chloride ion concentration, using a zero current over the cell membrane. To restore the previous chloride ion concentration after each measurement, a low amplitude current is applied until the net charge moved in the measurement period has flowed back. After each restoration of the chloride ion concentration, the voltage is again determined iteratively with a zero current over the cell membrane to give any correction required on a deviation of the zero current. A gas, saturated with steam, flows over the micro measurement chamber during a patch clamp measurement. For the measurement of aerobic conditions, for the autokrine activation of ion channels, the micro measurement chamber is gassed with oxygen saturated with steam. Two cells can be used, where one cell is for stimulation and the other is for the measurement of ion flows. A flow of argon saturated with steam is passed over the chamber for measurement under conditions of ischemia. At the same time as the measurements of ion flows, optical measurements are made of fluid movements and ion flows through the cell membrane using conventional fluorescent techniques.
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