FIGURE 4.

GABA concentration dependence of concatenated receptors. A, current traces from a GABA concentration-response curve obtained from a Xenopus oocyte expressing β₃-α₆-δ/α₁-β₃ (R13) receptors. The bars indicate the time period of GABA perfusion. GABA concentrations are indicated above the bars. B, averaged GABA concentration-response curves of β₃-α₁-δ/α₆-β₃ (R12), β₃-α₆-δ/α₁-β₃ (R13), α₆-β₃-α₁/β₃-δ (R23), and β₃-α₁-δ/β₃-α₆ (R52) receptors. The curves for β₃-α₆-δ/α₁-β₃ (R13) and β₃-α₁-δ/β₃-α₆ (R52) receptors are shown as fitted with a single component, and those for β₃-α₁-δ/α₆-β₃ (R12) and α₆-β₃-α₁/β₃-δ (R23) receptors are shown as fitted with a two components. Individual curves were first normalized to the observed maximal current amplitude and subsequently averaged. Mean ± S.D. of experiments carried out with 3–4 oocytes from two batches for each subunit combination is shown.