Differential effects of estrogen receptor alpha and beta specific agonists on social learning of food preferences in female mice

There is an evolutionary advantage to learning food preferences from conspecifics, as social learning allows an individual to bypass the risks associated with trial and error individual learning. The social transmission of food preferences (STFP) paradigm examines this advantage. Females in the proestrus and diestrus phases of the estrous cycle show a prolonged preference for the demonstrated food relative to estrus and ovariectomized females. Additionally, both estrogen receptor alpha (ER alpha) and estrogen receptor beta (ER beta) knockout mice show impaired social recognition, which suggests that both receptors may be involved in other types of socially dependent learning, including the STFP. The present study investigated the effect of the ER alpha selective agonist PPT (1,3,5-tris(4-hydroxyphenyl)-4-propyl-1H-pyrazole) and the ER beta selective agonist WAY-200070 (7-Bromo-2-(4-hydroxyphenyl)- 1,3-benzoxazol-5-ol) on the STFP. Results showed that ovariectomized (ovx) mice treated with PPT failed to learn the socially acquired preference, while WAY-200070-treated ovx mice showed a two-fold prolonged preference for the food eaten by their demonstrator. The effects of PPT on the socially acquired food preference cannot be explained by effects on the total food intake of the groups or on the type of interaction with the demonstrator mouse. The effects of WAY-200070 may be partially due to effects on Submissive Behavior. The higher WAY-200070 doses produced prolonged preferences similar to those seen previously in intact female mice during the proestrus and diestrus phases. This suggests that the estrous cycle's effects on social learning may be due to the action of ER beta on Submissive Behavior, or to ER beta countering that of ER alpha.