Effects of voluntary and involuntary exercise on cognitive functions, and VEGF and BDNF levels in adolescent rats

Abstract

Regular treadmill running during adolescence improves learning and memory in rats. During adolescence, the baseline level of stress is thought to be greater than during other periods of life. We investigated the effects of voluntary and involuntary exercise on the prefrontal cortex and hippocampus, vascular endothelial growth factor (VEGF), brain-derived neurotrophic factor (BDNF) levels, and spatial learning, memory and anxiety in adolescent male and female rats. The voluntary exercise group was given free access to a running wheel for 6 weeks. The involuntary exercise group was forced to run on a treadmill for 30 min at 8 m/min 5 days/week for 6 weeks. Improved learning was demonstrated in both exercise groups compared to controls. Neuron density in the CA1 region of the hippocampus, dentate gyrus and prefrontal cortex were increased. Hippocampal VEGF and BDNF levels were increased in both exercise groups compared to controls. In females, anxiety and corticosterone levels were decreased; BDNF and VEGF levels were higher in the voluntary exercise group than in the involuntary exercise group. The adolescent hippocampus is affected favorably by regular exercise. Although no difference was found in anxiety levels as a result of involuntary exercise in males, females showed increased anxiety levels, and decreased VEGF and BDNF levels in the prefrontal cortex after involuntary exercise.

Exercise Regulation of Cognitive Function and Neuroplasticity in the Healthy and Diseased Brain

“…17 However, rats exposed to forced exercise exhibit signs of stress such as increased anxiety levels. 18 Further, research shows that voluntary exercise produces more prominent plastic changes in the hippocampus when compared to the impact of forced exercise on the hippocampus. 21 This suggests that forced exercise may not be the best way to model aerobic activity in rodents as it unintentionally produces stress-inducing side effects that make it more difficult to tease apart the influence of exercise from psychological stress effects on the brain.…”

“…Voluntary wheel running increases the concentration of several different growth and trophic factors that likely support the morphological changes in the brain discussed above including fibroblast growth factor-2 (FGF-2), 48 insulin-like growth factor-1 (IGF-1), 49 brainderived neurotrophic factor (BDNF), 50 and vascular endothelial growth factor (VEGF) 18 among others. BDNF in particular appears to be especially susceptible to regulation by exercise.…”

Cardiometabolic and reproductive benefits of early dietary energy restriction and voluntary exercise in an obese PCOS-prone rodent model

“…The findings from this study demonstrate that early intervention at weaning in predisposed obese PCOS-prone animals can modulate hypothalamic regulatory pathways to improve adiposity, cardiometabolic and reproductive indices. The use of a voluntary wheel running protocol (which occurs under non-stressful conditions) as opposed to enforced treadmill running was used in this study, reflecting a measure of 'self-motivation' to exercise and therefore may best mimic voluntary exercise in the clinical setting (Uysal et al 2014). To our knowledge, studies using treadmill-enforced running have not been undertaken in weaning animals that are PCOS prone.…”

Effect of complex aerobic physical exercise on PSD-95 in the hippocampus and on cognitive function in juvenile mice

“…However, in the event of the activation of excess calpain molecules by the hormone CRH, the impact on the destabilization of the spinal dendrites can result in memory impairment [26]. Physical exercise increases the levels of the stress hormone, corticosterone [27,28] and adolescence is a period of high stress [27]. In this study, complex aerobic exercise performed during the growth stage was thought to induce physiological stress that played a role in the synapse remodeling that is important for learning and memory.…”