IBCN   20355
INSTITUTO DE BIOLOGIA CELULAR Y NEUROCIENCIA "PROFESOR EDUARDO DE ROBERTIS"
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
Aerobic exercise prevents age-dependent cognitive decline and reduces anxiety-related behaviors in middle-aged and old rats. Effects on the nitregic system
Autor/es:
PIETRELLI A; LOPEZ COSTA JJ; LOPEZ EM; GOÑI, R; BASSO, N; BRUSCO, A
Lugar:
New Orleans
Reunión:
Congreso; 42 Meeting of the Society for Neuroscience; 2012
Institución organizadora:
Society for Neuroscience
Resumen:
There is growing interest in studying factors related to lifestyle and interventions to improve the cognitive capability of older adults, and reduce the risk of neurodegenerative diseases associated with aging.Physical activity is considered one of the most important and accessible factors to prevent and protect brain functions at low cost. Extensive evidence from animal and human studies suggests that exercise has a positive impact on cognitive and emotional aspects of behavior. NO may also play a critical role in synaptic plasticity, aging and neurodegenerative processes. A positive association between NO,learning and memory has been detected. Previous results obtained in rats showed regional variations and age-related changes of NOS in the prefrontal and temporal cortex as well as in the hippocampal and parahippocampal regions.These variations seem to correlate significantly performance on various behavioral as:radial maze,water maze,plus maze, field,etc. It has been proposed that NO activity falls with aging. Studies performed in humans reported that exercise produces changes in the NOS/NO system that are tissue-specific and increases the plasma nitrite/nitrate, stable end-products of NO. Furthermore, it has been shown that NO bioavailability decreases with age and is significantly increased by aerobic training in elderly athletes. The protocol consisted of three stages:(1)Handling,(2) Shaping/habituation,and (3) Testing procedure. Formal training began on the 8th day after the first exposure to the maze. Each rat was tested for 10 min. The first 5 min corresponded to the acquisition phase,the latter to< the consolidation phase of memory. The following parameters were determined:(a) Correct entries (%): calculated as the percentage of right (baited) arm entries divided by total arm entries (baited/right and non baited/wrong), [(number of correct entries/number of arms)100];(b)Number of arms(NA,and wrong):arms visited in the allowed time; (c) Total time (TT, seconds): time needed to visit right arms; (d) Working memory errors (WME): number of reentries into a right arm already visited in the same session; (e) Spatial memory errors (SME): number of entries into a wrong arm; (f) Success: number of trials that met the following criteria: (1) four correct entries; (2) without errors in WME or SME,and (3)in time less than 3 min. Variable (f)was considered the main index of cognitive performance level achieved because it summarizes the remaining parameters. 1. Parieto-temporal cortex stained with the NADPH-d histochemical technique(Bregma level: −3 to − 4.3 mm. (a) Low magnification of parieto-temporal cortex showing the anatomica location and selected layers(III-V). Scale bar: 1mm.(b) NADPH-d reactive cortical neurons of SC.(c) NADPH-d reactive cortical neurons of AT rats. b-c: magnification: 200×; scale bar:100 μm. Observe the increase of size of nitrergic neurons,the number and length of dendritic branches in AT rats compared with SC. Note the rise of NADPH-d reactivity in AT neurons versus SC. AT sections also showed higher density of nerve fibres compared with their controls. (d)Somatic area of NADPH-d cortical neurons. Note that somatic cell size is significantly higher in AT than in SC, consistent with that observed in b-c.(e)Optical density NADPH-d stained neurons. Data are expressed in ROD units.(f) Integrated optical density (IOD) of the stained NADPH-d neurons.Data are expressed in ROD units.μm2.The increase in the ROD and IOD in trained rats shows that the NADPH-d reactivity is higher and the staining pattern covered larger areas than in the SC group. Graphs d, e and f: bars represent the mean ± S.E.M. of 30 NADPH-d reactive cells belonging to groups. Conclusions:1. Aerobic exercise practiced throughout life, acted on a time and dose-dependent manner, produced plastic effects on the brain and behavior, and these effects were modulated by age. 2. Mild-moderate stress produced during aerobic exercise results in favorable homeostatic adaptations that protect organisms against more severe stress or anxiety-related disorders. 3. Aging increased anxiety-related behaviors, and moderate and regular exercise improved the cognitive performance, and positively affected emotional aspects of behavior, leading to a better management of stress. These beneficial effects were important in old age. 4. Our work also provides new evidence of the neuroprotective and restorative properties of regular physical activity on the cognitive decline associated with aging, and its ability to reverse the potentially negative effects of inactivity. 5. Moderate exercise had a relevant effect on spatial and procedural memory, and motor learning. As there is a temporal correlation between the two phenomena, nNOS/NADPH-d upregulation and behavioral improvement that NO may be involved in the neurophysiological response to chronic aerobic exercise could be suggested.