Fig. 3.

Patch-clamp electrophysiological characterization of homomeric GlyRα1 wildtype and GlyRα1^P1-5A mutant receptors. (A) Current responses of human wildtype GLRA1 (hs GlyRα1-wt) and mutant receptors GlyRα1^P1-5A. Whole-cell patch clamp currents were recorded from transfected HEK293 cells at glycine concentrations between 10 and 1000 μM and a membrane potential of −50 mV. (B) Dose response curve of α1-wt (solid squares, solid line) and GlyRα1^P1-5A (open circles and dashed line). EC₅₀ values were 38.4 ± 3.4 μM for α1-wt (n = 20) and 56.9 ± 4.4 μM (n = 9) for the mutant receptor. Hill constants were 1.9 ± 0.1 and 2.0 ± 0.1 for wildtype and mutant, respectively. (C) Current potential curves were measured at 2 mM glycine in a potential range of −60 mV to +60 mV. Current responses were normalized to maximal currents at −60 mV. (D) Comparison of wildtype and mutant receptor dose responses; the difference was statistically significant (p = 0.016).