Comparison of the effects of vinpocetine, vincamine, and nicergoline on the normal and hypoxia‐damaged learning process in spontaneously hypertensive rats

Vinpocetine (Cavinton®), vincamine, and nicergoline (Sermion®) were evaluated for the ability to protect cognitive function of spontaneously hypertensive rats from the damaging effect of hypoxia. Normobaric hypoxia (6% oxygen) was applied during the acquisition of a two‐way active avoidance task (3 sessions, 50 trials/session). Hypoxia decreased the percentage of conditioned avoidance responses by 50% on day 3. Vinpocetine (1.25–10 mg/kg) administered orally 60 min prior to the daily sessions did not significantly improve learning in normoxic conditions; however, it prevented hypoxia‐induced learning deficit (1.25 mg/kg peak effect dose). The dose‐response relationship for the compound is an inverted U‐shaped curve. Vincamine (2.5–20 mg/kg p.o.) did not facilitate learning under normoxic conditions, but afforded protection against hypoxia at the 20‐mg/kg dose. Nicergoline (2.5–20 mg/kg p.o.) did not increase acquisition of the normoxic avoidance response, and it also showed a moderate antihypoxic effect. Vinpocetine, and to a lesser degree vincamine and nicergoline–‐drugs useful in the therapy of cognitive disturbances following cerebral ischemichypoxic states–‐proved effective in the prevention of a hypoxia‐induced learning deficit.