title: Treadmill exercise inhibits hippocampal apoptosis through enhancing N-methyl-D-aspartate receptor expression in the MK-801-induced schizophrenic mice.
abstract: Schizophrenia is a severe mental disorder characterized by abnormal mental functioning and disruptive behaviors. Abnormal expression of N-methyl-D-aspartate (NMDA) receptor, one of the glutamate receptor subtypes, has also been suggested to contribute to the symptoms of schizophrenia. The effect of treadmill exercise on schizophrenia-induced apoptosis in relation with NMDA receptor has not been evaluated. In the present study, we investigated the effect of treadmill exercise on neuronal apoptosis in the hippocampus using MK-801-induced schizophrenic mice. MK-801 was intraperitoneally injected once a day for 2 weeks. The mice in the exercise groups were forced to run on a treadmill exercise for 60 min, once a day for 2 weeks. In the present results, repeated injection of the NMDA receptor antagonist MK-801 reduced expression of NMDA receptor in hippocampal CA2-3 regions. MK-801 injection increased casapse-3 expression and enhanced cytochrome c release in the hippocampus. The ratio of Bax to Bcl-2 was higher in the MK-801-induced schizophrenia mice than the normal mice. In contrast, treadmill exercise enhanced NMDA receptor expression, suppressed caspae-3 activation and cytochrome c release, and inhibited the ratio of Bax to Bcl-2. Based on present finding, we concluded that NMDA receptor hypofunctioning induced neuronal apoptosis in MK-801-induced schizophrenic mice. Treadmill exercise suppressed neuronal apoptosis through enhancing NMDA receptor expression in schizophrenic mice.
authors.affiliation: Department of Urology, Gachon University Gil Medical Center, Gachon University, Incheon, Korea.
authors.forename: Jin Woo
authors.initials: JW
authors.lastname: Chung
authors.affiliation: Division of Sports Science, Baekseok University, Cheonan, Korea.
authors.forename: Jin-Hee
authors.initials: JH
authors.lastname: Seo
authors.affiliation: Department of Psychiatry, Gangneung Asan Hospital, University of Ulsan College of Medicine, Gangneung, Korea.
authors.forename: Sang-Bin
authors.initials: SB
authors.lastname: Baek
authors.affiliation: Department of Physiology, College of Medicine, Kyung Hee University, Seoul, Korea.
authors.forename: Chang-Ju
authors.initials: CJ
authors.lastname: Kim
authors.affiliation: Department of Physiology, College of Medicine, Kyung Hee University, Seoul, Korea.
authors.forename: Tae-Woon
authors.initials: TW
authors.lastname: Kim
keywords: Apoptosis; Mice; N-methyl-D-aspartate receptor; Schizophrenia; Treadmill exercise