engleski

Passive avoidance behaviour changes produced by the atropinisation and the nucleus basalis lesion in rats

The nucleus basalis magnocellularis (NB) provides the primary cholinergic input to the cortical mantle. Numerous laboratories have implicated deficiences in cholinergic function as contributing to the loss of memory in old age as well the more severe cognitive disturbances occurring with Alzheimer 's disease. The study was carried out on Wistar albino rats weighting 200- 250 g. Cholinergic deficit was produced by the atropinisation or by electrolytic or neurotoxic lesion of the NB. Atropin sulphate (6mg.kg-1) or 0.9% NaCl solution was injected i.p. to intact animals half an hour before the passive avoidance test started. All the other animals were anesthetized and placed on a stereotaxic frame. Bilateral or unilateral electrolytic NB lesions were made by using a direct current of 1.0 mA passed through a unipolar electrode for 30 sec. Unilateral neurotoxic lesions of the NB were made by application of 1.0 μ g kainic acin in 1.0 μ l sodium phosphate buffer. After a 15 days lasting postoperative recovery period passed, each the NB lesioned animal was subjected to the passive avoidance test. The results of our experiment show that an impairment of the cholinergic function, either by the atropinisation or by the NB lesions, produced marked deficit in the passive avoidance behavior in rats. Atropine was more effective than the NB lesions in reducing of the memory performance in rats. Therefore, we suggest that other cholinergic mechanisms originating outside the NB are also involved in the learning processes.

passive avoidance behavior ; atropin ; nucleus basalis ; rat

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