A point mutation was introduced that altered codon 101 from one encoding histidine to one encoding arginine (H101R). This alteration had been shown to render the GABA-A receptor insensitive to drugs such as diazepam. A loxP flanked neomycin selection cassette was also inserted into an adjacent intron, but was removed by Cre mediated recombination in the final allele. (J:62214)