Macroscopic Kinetics of Pentameric Ligand Gated Ion Channels: Comparisons between Two Prokaryotic Channels and One Eukaryotic Channel
Figure 2
Outside-out patch-clamp recordings from HEK-293T cells expressing GABAARs.
A) Current evoked by a 1 second pulse of 10 mM GABA. The current decrease in the presence of agonist (desensitization) and upon agonist washout (deactivation) were fit with bi-exponential functions (red curves) and the weighted time constants for the example trace are shown. B) Current evoked by a 5 millisecond application of 10 mM GABA (black arrow). To the right, expanded traces highlight the current increase during GABA application (activation) and the current deactivation following washout of GABA. The time course of activation was determined by fitting the rising phase with a bi-exponential function (red curve) and the timecoure of deactivation was determined by fitting the current decay after agonist removal with a bi-exponential function (red curve). The weighted time constants for the example traces are shown. The traces shown are the ensemble averages of multiple GABA-evoked currents from a single patch.