Treatment Period 1: Naive Rats | Treatment Period 2: Tolerant Rats | Treatment Period 3: Tolerant Rats |
---|---|---|
5 mg/24 h i.v. oxycodone (n = 8) | 20 mg/24 h i.v. morphine (n = 4) | |
5 mg/24 h i.v. oxycodone (n = 4) | ||
20 mg/24 h i.v. morphine (n = 8) | 5 mg/24 h i.v. oxycodone (n = 4) | |
20 mg/24 h i.v. morphine (n = 4) | ||
Oxycodone i.v. infusion, 2.5 mg/24 h for 60 h | i.v. bolus dose of morphine | i.v. bolus dose of oxycodone |
1,402 nmol (n = 4) | 2,220 nmol (n = 4) | |
2,803 nmol (n = 4) | 3,171 nmol (n = 6) | |
3,504 nmol (n = 7) | 3,805 nmol (n = 4) | |
4,205 nmol (n = 4) | 4,756 nmol (n = 4) | |
7,008 nmol (n = 4) | 9,513 nmol (n = 4) | |
Morphine i.v. infusion, 10 mg/24 h for 60 h | i.v. bolus dose of oxycodone | i.v. bolus dose of morphine |
317 nmol (n = 4) | 3,504 nmol (n = 4) | |
951 nmol (n = 4) | 4,205 nmol (n = 6) | |
1,585 nmol (n = 8) | 4,906 nmol (n = 4) | |
2,537 nmol (n = 8) | 6,308 nmol (n = 6) | |
6,342 nmol (n = 4) | 10,514 nmol (n= 4) | |
i.v. bolus dose of oxycodone | ||
79 nmol (n = 4) | ||
159 nmol (n = 4) | ||
317 nmol (n = 6) | ||
476 nmol (n = 6) | ||
1,585 nmol (n = 5) | ||
i.v. bolus dose of morphine | ||
350 nmol (n = 4) | ||
701 nmol (n = 4) | ||
1,402 nmol (n = 4) | ||
1,752 nmol (n = 4) | ||
3,504 nmol (n = 4) | ||
i.v. bolus dose of saline (n = 4) |
↵1-a Each treatment period was followed by a 12-h washout period with saline.