Figure 6: Simulation of GABA currents after block by and recovery from PTX.
From: The desensitization gate of inhibitory Cys-loop receptors
(a–c) Left: kinetic models 1–3 used to predict the recovery of agonist-induced currents after wash-out of PTX (or P) in the presence of saturating concentrations of the agonist ([A]; 10 mM GABA). Receptors states are: R inactive, agonist-unbound receptor; AR inactive, agonist-bound receptor; AR* agonist-bound activated receptor; AD agonist-bound desensitized receptor, all with or without bound PTX. Right: predicted membrane currents, generated from the models, for wild-type α1β2 GABAARs activated by 10 mM GABA in the presence and absence of 50 μM PTX. See Supplementary Table 2 for the numerical values of the parameters. (a) Model 1: the PTX-blocked open receptor (AR*P) can desensitize, but PTX binding and unbinding cannot occur to or from either the resting (R/RP, AR/ARP) or desensitized (AD/ADP) receptor states. (b) Model 2: PTX binding and unbinding is permitted to both open (AR*/AR*P) and desensitized states. (c) Model 3: PTX binding prevents desensitization (that is, there is no ADP state).
