pcDNA3-based expression constructs containing coding sequence for rat GIRK1, mouse GIRK2a (NM_001025584.2, initially referred to as Girk2-1: NP_001020755, AAC34284), and mouse GIRK2c (NM_010606.2, initially referred to as Girk2-A or Girk2A-1: NP_034736, AAC34285, P48542), as well as mouse GABABR1 and GABABR2 (provided by Dr. Paul Slesinger), were used for HEK293 cell transfection and electrophysiology studies. AAV vectors used for expression of GIRK2a or GIRK2c were generated by sub-cloning GIRK2a/c-IRES-EGFP cassettes into the backbones of pAAV-hSyn-TRβ-IRES-EGFP (provided by Dr. Bernd Gloss), pAAV-CaMKIIα-hChR2(C128S/D156A)-mCherry (provided by Dr. Karl Deisseroth; Addgene plasmid #35502)69, and pAAV-hSyn-DIO-hM4D(Gi)-mCherry (provided by Dr. Bryan Roth; Addgene plasmid #44362)70 plasmids. The AAV Helper-Free System was used for viral packaging (Agilent Technologies; Santa Clara, CA). AAV particles were obtained by co-transfecting pHelper (provided by Dr. David Armstrong), pAAV-RC2/8 (UPenn Viral Vector Core), and pShuttle plasmids into AAV293 cells using the polyethylenimine (PEI) method (Polysciences, Inc.; Warrington, PA). For each 15-cm plate, a total of 100 μg of DNA (33.3 μg of each plasmid) was added to a 150 mM NaCl solution, in a final volume of 2 mL; 12.5 μL of PEI
