Streptozotocin-induced sporadic Alzheimer's disease: selection of appropriate dose.

The long term effect of single (day 1) and twice (day 1 and 3) injections of intracerebroventricular (ICV) streptozotocin (STZ) at the doses of 1 and 3 mg/kg on the cognitive functions of male Wistar rats was evaluated. Elevated plus maze, passive avoidance, and Morris water maze tests were used to assess the cognitive functions. A significant cognitive deficit was found at the 2nd week onwards, which persisted up to the 14th week with single and twice ICV-STZ (3 mg/kg) injections, whereas no cognitive impairment was found in ICV-STZ (1 mg/kg) treated groups after 8-10 weeks.