Figure 1:

Experimental protocol timeline. Rats were allotted 7 d for recovery from surgery and 8 d for baseline measurements, which included diurnal and restraint stress ACTH and corticosterone. After 10 d of sucrose SA and 10 d of oxycodone SA during a 26-d timespan, rats entered the abstinence phase and were acclimated to the sleep restriction apparatuses. During the next 35 d of abstinence, sleep restriction or ambulation control conditions were carried out. HPA axis assessments were repeated on Days 20-23 of sleep restriction or control conditions. The final nine experimental days of sleep restriction or control conditions were composed of extinction testing, footshock reinstatement, and tissue harvests.

Figure 1 Alt Text: Protocol: HPA dynamics in rats before and during abstinence from opioids; during the abstinence period, rats underwent a sleep restriction protocol or were ambulatory controls.