TABLE 1

Ten-day morphine and heroin dosing schedule On the 10th day, rats were euthanized 4 h after the final morphine or heroin injection.




Days 1–2

Days 3–4

Days 5–6

Days 7–8

Days 9–10
mg/kg
Morphine
   Mor10/120 10 20 40 80 120
Heroin
0.5
1
2
4
8