OBJECTIVE To investigate the training, extinc tion with cue isolation and reinstatement models of heroin see king.METHODS Training: Male Sprague-Dawley rats were self-administered heroin on a fixed ratio 1 and 2 (FR1 and 2) schedule of reinforcement with touching the active nose poke as the operant behavior during 14 daily 4 h sessions.Extinction: ① The rats were placed into the operant chamber and allowed to nose poke resulted in all of the same consequences during the training period, but saline, rather than heroin, was infused until active and inactive number similar to each other.