The anion selectivity of the gamma-aminobutyric acid controlled chloride channel in the perfused spinal ganglion cell of frog.

The selectivity of the GABA-controlled Cl- channel in the membrane of the dorsal root ganglion cell of the frog has been measured in internally perfused cells by means of current and voltage clamp. When Cl- was replaced by various anions, the 10(-5) or 10(-4) M GABA-induced reversal potentials (EGABA) for Br-, I-, NO3-, ClO4-, SCN-, BF4- and ClO3- were more negative than that for Cl-, despite the fact that, in solution, the test anions are either larger than or similar in size to Cl-.