The Basics of Electrical Coupling

摘要: Cells are said to be electrically coupled when ionic current injected into one cell passes the cell’s neighbour. Fig. 1 a illustrates electrical circuit in simplest case, only two cells present. In a), simply apposed, and membranes assumed homogeneous, that is say no junctions Two microelectrodes inserted 1, first injects cell, second measures voltage across membrane, by comparison with reference electrode bath. Current pulses give rise deflections proportional membrane resistance (Ohm’s law). These not instantaneous, because acts as capacitor, which charged discharged at each pulse. Cell 2 impaled voltage-recording microelectrode. What does this see ? absence of true coupling, still close enough another capacitively coupled, but steady can flow from another. If looks more closely space separating membranes, it becomes clear ions, having crossed under influence pulse, have so speak choice between entering or going earth. Even if pushed against another, earth much lower than other all goes way.