Oxycodone self-administration.

Oxycodone abuse frequently begins with prescription oral oxycodone, yet vulnerability factors (e.g. sex, genetics) determining abuse are largely undefined. We evaluated genetic vulnerability in a rat model of oral oxycodone self-administration (SA): increasing oxycodone concentration/session (0.025-0.1mg/ml; 1-, 4-, and 16-h) followed by extinction and reinstatement. Active licks and oxycodone intake were greater in females than males during 4-h and 16-h sessions (p h2) of active licks during 4-h sessions at increasing oxycodone dose ranged from 0.30 to 0.53. Under a progressive ratio (PR) schedule, breakpoints were strain-dependent (p