Similar plasma corticosterone levels in LCRs, HCRs, and saline-treated controls. Plasma corticosterone levels were measured (a) on Day 0 (baseline) and then on Day 1 before (−30 min) and after (20, 40, and 60 min) injection of cocaine or saline (see Fig.1b) and (b) similarly on Days 4 and 5 of the repeated cocaine or saline protocol (see Fig.1c). n=8 (HCR), n=8 (LCR), n=8 (Saline), except on Days 1 and 4 when blood samples could not be collected from one Saline animal due to a temporarily clogged catheter. Mean ± SEM.