Treadmill exercise ameliorates disturbance of spatial learning ability in scopolamine-induced amnesia rats

Alzheimer's disease is the most common neurodegenerative disease and this disease induces progressive loss of memory function Scopolamine is a non-selective muscarinic cholinergic receptor antagonist and it induces impairment of learning ability. Exercise is known to ameliorate memory deficits induced by various brain diseases. In the present study, we investigated the effect of treadmill exercise on spatial learning ability in relation with cell proliferation in the hippocampus using the scopolamine-induced amnesia mice. For the induction of amnesia, 1 mg/kg scopolamine hydrobromide was administered intraperitoneally once a day for 14 days. Morris water maze test for spatial learning ability was conducted. Immonofluorescence for 5-bromo-2-deoxyuri-dine (BrdU) and western blot for brain-derived neurotrophic factor (BDNF) and its receptor tyrosine kinase B (TrkB) were performed. In the present results, scopolamine-induced amnesia mice showed deterioration of spatial learning ability. Inhibition of cell proliferation and suppression of BDNF and TrkB expressions were observed in the scopolamine-induced amnesia mice. Treadmill exercise improved spatial learning ability and increased cell proliferation through activating of BDNF-TrkB pathway in the amnesia mice. These findings offer a possibility that treadmill exercise may provide preventive or therapeutic value for the memory loss induced by variable neurodegenerative diseases including Alzheimer's disease.