Macroscopic Kinetics of Pentameric Ligand Gated Ion Channels: Comparisons between Two Prokaryotic Channels and One Eukaryotic Channel
Figure 8
GLIC current activation was slow and deactivation fast compared to GABAARs.
A) GLIC currents activated by a 2 s application of pH 4.0 buffer exhibited two different desensitization profiles. In 25 patches, little current desensitization was observed, whereas in 18 patches, a fast component of desensitization was observed. GLIC current activation and deactivation was analyzed separately for each group. Expanded views of current activation and deactivation are shown to the right and fit with bi-exponential functions (red curves). B) The τw-activations for GLIC currents (pH 4.0) from both groups are plotted and compared to the τw-activations of currents obtained from patches from mock-transfected cells (pH 4.0) and from GABAARs (10 mM GABA). Data are mean ± SEM (GLIC no early: n = 25, GLIC w/early: n = 18, Mock: n = 7). C) The τw-deactivations are plotted for both groups of GLIC currents following a 2 s (as shown above) as well as a 25 s pulse of pH 4.0 buffer. The τw-deactivations for GABAAR currents evoked by 5 ms or 1 s applications of 10 mM GABA are also plotted. Data are mean ± SEM (GLIC no early 2 s: n = 11, GLIC no early 25 s: n = 8, GLIC w/early 2 s: n = 6, GLIC w/early 25 s: n = 6).