Treadmill exercise improved memory evocation and upregulated Alpha7 nicotinic receptors density in lower cognitive performance rats

Abstract

Chronic and moderate exercise promotes biochemical and physiological changes in the organism, leading to, among other benefits, improves in cognitive deficits. Formation of long-term memory can be modulated by α7 cholinergic nicotinic receptors (nAChR). However, until now there is no evidence that physical exercise could ameliorate the functioning of the cholinergic system and contribute to memory improvement in animals with learning and memory difficulties. This study evaluated the effects of moderate exercise to the memory and the density of α7 nAChR in less-responsive rats to active avoidance task. Male Wistar rats (300-470 g) were submitted to active avoidance apparatus and those that had a bad performance were classified as lessresponsive rats. Part of these animals were submitted to a moderate physical training on treadmill for one hour per day, five days per week, during eleven weeks. The other half was left in cages (sedentary group). On the end of this period, trained animals presented significant reduction on the blood pressure, when compared to their sedentary controls and an improve of 2.95 times in memory. After that, brains were extracted and submitted to autoradiography for α7 nAChR using [125I]-α-bungarotoxin. It was observed a significant increase in the density of this receptor in the hippocampus and in the shell portion of nucleus accumbens of trained animals when compared to sedentary ones. In conclusion, moderate physical exercise improved memory evocation of less-responsive animals and increased the density of α7 nAChR. These data reinforce the importance of the moderate exercise to those who present learning and memory difficulties.