Aims: 

Cholinergic neurotransmission is a crucial process underlying memory and cognitive functions. Some cortical cholinergic activity is lost during normal aging, while neurodegeneration related dementias display a severe degeneration of cholinergic neurons. Endogenous neuroprotective processes, like the function of estrogen receptors in the cognitive brain areas, need also maintenance for functional reserves. To build up cognitive brain reserve the preventive role of regular physical exercise merits consideration. In animal experiments the effects of long-term physical exercise were studied on psychomotility, attention, learning, and memory functions during the course of aging in rats. For neuromorphological background density of estrogen receptor alpha (ERa), that of cholinergic fibres and their axonal aberrations, and capillary density were measured in hippocampus and other brain areas.

Methods: 

Malerats of 6, 18 and 26 months old were trained in treadmill for 6 months. At the end of training period cognitive behaviours were tested: exploration, attention and Morris water maze spatial learning. After brain fixation immunohistochemical analysis of ERa, ChAT positive cholinergic structures and brain capillary density were analyzed.

Results: 

Marked regressions in behavioural functions like psychomotility, attention and spatial learning could be recorded across aging. Training counterbalanced motility and spatial learning declines in very old animals, attention was improved mainly in young rats. ERa density in the CA3 area of hippocampus declined also markedly and the training was beneficial in the old ages. An age-related loss of cholinergic fibres and an increased density of fibre aberrations were recorded. The mortality rate in the very old age (26–32 mo) declined significantly by the training.

Conclusions: 

In rats aging deteriorates cognitive and motor functions significantly. Moderate intensity chronic physical exercise, however, exerts detectable improvement in behaviour and brain functions. In the oldest group frailty syndrome develops and physical exercise is significantly effective in its prevention and ultimately decreased mortality.