Gender-dependent regulation of anxiety-like behavior by δ subunit-containing GABAA receptor during postnatal development

: The δ subunit-containing GABAA receptor [GABAA(δ)R], which is exclusively situated in the extrasynaptic space, has considerable influence on emotion and behavior. Although the expression of this receptor experiences dramatic fluctuation during postnatal development, it remains unknown whether it regulates emotion in a development-dependent manner. Here, by using mice with genetic deletion of GABAA(δ)R (knockout) and their wild-type littermates, we examined the role of GABAA(δ)R in regulating anxiety-like behavior, as measured with open field test (OFT) and elevated plus maze during the transition from puberty to adulthood. We observed that for female mice, the knockout ones at puberty but not adulthood showed increased anxiety-like behavior in the OFT relative to their wild-type littermates. However, such increase was not observed in elevated plus maze. For male mice, no between-genotype differences were observed in both tests at the above two developmental stages. Our results suggest that GABAA(δ)R preferentially affects the anxiety-like behavior in OFT in a development-dependent manner, but only in female mice.