2.8. Naloxone‐precipitated withdrawal

For https://www.guidetopharmacology.org/GRAC/LigandDisplayForward?ligandId=1638‐precipitated withdrawal mice were chronically (at 8:00 and 16:00 for five consecutive days) treated with saline, morphine or PZM21, as described by Abdel‐Zaher, Hamdy, Aly, Abdel‐Hady, and Abdel‐Rahman (2006). On the sixth day, 3 hr after the final saline or drug administration, all animals received 4 mg·kg⁻¹ naloxone and immediately after the injection each animal was placed in a transparent acryl cylinder (20 cm in diameter, 50 cm in height) for 15 min to observe jumps, which were considered as a manifestation of withdrawal.