engleski

The effects of calcium channel blockers nimodipine and nicardipine and nootropic drugs piracetam and oxiracetam on hypoxia-induced memory impairment in the rat

CerebraI hypoxia is associated with a various functional disturbances and damage of neurons. The most important consequence is an influx of calcium from the extracellular to the intracellular compartment. Consequently vascular and metabolic disturbances occur. Therefore, we investigated the effects of calcium channel blockers (nimodipine, nicardipine) and metabolic enhancers (piracetam, oxiracetam) on hypoxia induced cognitive deficit in the rat. The study was carried out on Hannover- Wistar rats weighing 250 gr. Various doses of nimodipine and nicardipine (0.03 ; 0.1 ; 0.3 ; 1, 0 mg/kg) or piracetam (30 ; 100 ; 300 mg/kg) or oxiracetam (50 ; 100 ; 300 mg/kg) were given intraperitoneally. Thirty or sixty minutes later passive avoidance task was performed according to the step-through procedure modified by Jarvik and Kopp (1967). Immediately after the training, animals were subjected to a period of oxygen deprivation hypoxia. Rats were placed into hypoxia cage and the percentage of oxygen was gradually reduced and continously measured. The level of 3, 5 V% of oxygen was reached in about twenty minutes and maintained up to the loss of righting reflex. Twenty four hours later passive avoidance retention was tested by using mentioned step- through procedure. It has been found that all tested drugs were effective in reversing the memory deficits in hypoxia exposed rats. All tested doses of mentioned substances led to significant enhancement of the passive avoidance in hypoxia treated rats.

nimodipine; nicardipine; nootropic drugs; hypoxia; passive avoidance; rat

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