Estrogen Receptor α Influences Socially Motivated Behaviors

Abstract

Male mice lacking estrogen receptor α (ERαKO) show reduced social behaviors. We hypothesized that this might be due to either socially elicited or generalized anxiety. Male ERαKOs and wild type (WT) mice were given a series of behavioral tests: elevated plus maze, T-maze, and social recognition. Each test included a social dimension by exposing males to ovariectomized (OVX) females. In addition plasma concentrations of corticosterone were measured, and open field activity was assessed. In the elevated plus maze, WT males exposed to an OVX female 1 min prior to the test were more anxious than WT controls. ERαKO males showed anxiety in this test whether or not they were preexposed to a female. In the T-maze, WT males increased exploration of a novel arm when it contained an OVX female. The presence or absence of a female in a novel arm did not affect behavior of ERαKO males. In social recognition tests, ERαKO males spent less time than WT littermates investigating an OVX female that was repeatedly introduced into their home cage. On the final trial, when a novel female was introduced, WT males increased their chemo-investigation but ERαKOs did not. Plasma corticosterone levels were lower in ERαKO than in WT males when plasma was taken directly after a brief (control) cage disturbance. In the open field WT and ERαKO males behaved essentially the same. Taken together, the results of these experiments suggest the ERαKO males avoid contact with other conspecifics, perhaps due to an inability to be aroused by social cues.