All animal procedures were approved by the Animal Care and Use Committee at Indiana University School of Medicine. GABAA receptor proteins were expressed in Xenopus laevis oocytes after injection of in vitro transcribed mRNAs. Full-length cDNAs of each of the cloned subunits were used to generate mRNA from the T7 RNA polymerase promoter using an in vitro transcription kit (mMessage Machine, Ambion, Austin TX). RNA concentration and quality was determined by both gel electrophoresis and UV spectrophotometry. Oocytes were harvested from mature Xenopus laevis, and follicle cells were removed with 2 mg/ml collagenase type IA (Sigma, St. Louis, MO). Stage V and VI oocytes were injected with 5–30 ng of each GABAA receptor subunit mRNA as indicated in a total of 50 nL of RNAse-free H20 using a Drummond automatic microinjector. Seven ratios of GABAA subunits were tested: 1) α2β2 only in a 1:1 ratio (10 ng:10 ng); 2) α2β2γ3 in a 1:1:3 ratio (10 ng:10 ng:30 ng); 3) α2β2γ3 in a 1:1:1 ratio (10 ng:10 ng:10 ng); 4) α2β2γ3 in a 3:1:1 ratio (30 ng:10 ng:10 ng); 5) α2β2γ3
