Estradiol increases choice of cocaine over food in male rats.

TitleEstradiol increases choice of cocaine over food in male rats.
Publication TypeJournal Article
Year of Publication2017
AuthorsBagley JR, Adams J, Bozadjian RV, Bubalo L, Ploense KL, Kippin TE
JournalPhysiol Behav
Date Published2017 Oct 19
ISSN1873-507X
Abstract

Estradiol modulates the rewarding and reinforcing properties of cocaine in females, including an increase in selection of cocaine over alternative reinforcers. However, the effects of estradiol on male cocaine self-administration behavior are less studied despite equivalent levels of estradiol in the brains of adult males and females, estradiol effects on motivated behaviors in males that share underlying neural substrates with cocaine reinforcement as well as expression of estrogen receptors in the male brain. Therefore, we sought to characterize the effects of estradiol in males on choice between concurrently-available cocaine and food reinforcement as well as responding for cocaine or food in isolation. Male castrated rats (n=46) were treated daily with estradiol benzoate (EB) (5μg/0.1, S.C.) or vehicle (peanut oil) throughout operant acquisition of cocaine (1mg/kg, IV; FI20 sec) and food (3×45mg; FI20 sec) responding, choice during concurrent access and cocaine and food reinforcement under progressive ratio (PR) schedules. EB increased cocaine choice, both in terms of percent of trials on which cocaine was selected and the proportion of rats exhibiting a cocaine preference as well as increased cocaine, but not food, intake under PR. Additionally, within the EB treated group, cocaine-preferring rats exhibited enhanced acquisition of cocaine, but not food, reinforcement whereas no acquisition differences were observed across preferences in the vehicle treated group. These findings demonstrate that estradiol increases cocaine choice in males similarly to what is observed in females.

DOI10.1016/j.physbeh.2017.10.018
Alternate JournalPhysiol. Behav.
PubMed ID29056351
PubMed Central IDPMC5908759
Grant ListR01 DA027525 / DA / NIDA NIH HHS / United States