Vinpocetine enhances retrieval of a step-through passive avoidance response in rats.

Vinpocetine, vincamine, apovincaminic acid, vinconate, aniracetam, Hydergine, and pemoline were evaluated for their ability to enhance retrieval of a step-through passive avoidance response in rats. The percentage of rats performing the avoidance response was found to decrease as a function of the number of days between training and retention testing (Day 1, 100%; Day 2, 65%; Day 3, 23%; Days 4 and 5, 0%). Vinpocetine administered 60 minutes prior to testing for retention significantly increased the number of rats performing the passive avoidance response. Retrieval enhancement was dose-related in an inverted U-shaped function with the effective doses at 18 and 30 mg/kg PO. In contrast, apovincaminic acid (1-400 mg/kg PO), vincamine (1-200 mg/kg PO), vinconate (1-200 mg/kg PO), aniracetam (1-300 mg/kg PO), Hydergine (0.1-10 mg/kg PO), and pemoline (1-30 mg/kg PO) were not effective. These data support the view that vinpocetine has cognition-activating abilities as defined in an animal model of memory retrieval.