Figure 5.

Subnanomolar concentrations of muscimol evoked currents on recombinant δ subunit‐containing GABA_ARs. Representative concentration‐response data (out of 3 similar recordings made using injections into different batches of oocytes) using muscimol concentrations from 0.1 nM up to 100 μM on (a) α4β3δ‐ or (c) α4β3‐injected oocytes. Muscimol concentrations from 0.1 nM to 30 nM activate currents only in α4β3δ‐injected oocytes, but not in the absence of δ subunits in α4β3 injected oocytes. (b) Slow current activation (association rates are slow at these low muscimol concentrations because association is concentration‐dependent) and also current deactivation at the lowest doses (expanded in b) and the two‐component decay for doses ≥ 10 nM. (d) Superimposed responses to 300 nM muscimol from α4β3δ‐ and α4β3‐injected oocytes. The responses were scaled so that the α4β3 300 nM muscimol current fits the fast current component in α4β3δ‐injected oocytes.