Modulation of the acetylcholine-catecholamine balance in the cognitive processes and its correlations with the oxidative stress

Background

Impairments of cognitive performance have been observed our previous studies in normal rats with muscarinic acethylcholine receptors (mAchRS), beta-adrenergic receptors (β AR) and D2-dopamine receptors (D2R) blockade, suggesting that these receptors have a facilitator role in learning and memory processes. Learning and memory processes are coordinated with different brain regions [1]. Since the oxidative damage may play a role in the aging process [2], including the associated decline, age-related impairment in spatial learning and memory may be alleviated by antioxidant treatment [3].

Materials and methods

Learning and memory tasks : Y-maze task; Step-through passive avoidance task.

Biochemical estimation : Determination of superoxid dismutaze (SOD), Determination of glutathione peroxidase (GPX), Determination of malondialdehyde (MDA).

Results

We observed that the levels of superoxide dismutase (SOD) and glutathione peroxidase (GPX) decrease in rats with mAchRS, D2R and β AR blockade by means of scopolamine (0.75 mg/kg b.w., i.p.), spiperone (0.4 mg/kg b.w.,i.p.) and propranolol (12 mg/kg b.w., i.p.), respectively, and the level of malondialdehyde (MDA) increase in the same rats, compared with saline-treated rats.

Conclusions

Muscarinic cholinergic and dopaminergic systems have a facilitating effect on mechanism that operates during the storage of information as memory engrams. We demonstrated that the increased oxidative stress is followed by cognition impairment in rats. Our findings support the hypothesis that oxidative stress plays a crucial role in brain dysfunction, contributing to the learning and memory deficits in rats.