Morphine physical dependence was induced on day 10 in SD rats by daily administration of morphine sulphate(MS), but not morphine hydrochloride(MH), in their drinking water.

在饮水中溶入硫酸吗啡，逐日提高吗啡浓度，SD大鼠在饮入吗啡后第10天产生明显的吗啡依赖。而同样方法饮入盐酸吗啡效果较差。