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jtitle_s:("Age (dodr)")
1.  Interaction between age of irradiation and age of testing in the disruption of operant performance using a ground-based model for exposure to cosmic rays 
Age  2011;34(1):121-131.
Previous research has shown a progressive deterioration in cognitive performance in rats exposed to 56Fe particles as a function of age. The present experiment was designed to evaluate the effects of age of irradiation independently of the age of testing. Male Fischer-344 rats, 2, 7, 12, and 16 months of age, were exposed to 25–200 cGy of 56Fe particles (1,000 MeV/n). Following irradiation, the rats were trained to make an operant response on an ascending fixed-ratio reinforcement schedule. When performance was evaluated as a function of both age of irradiation and testing, the results showed a significant effect of age on the dose needed to produce a performance decrement, such that older rats exposed to lower doses of 56Fe particles showed a performance decrement compared to younger rats. When performance was evaluated as a function of age of irradiation with the age of testing held constant, the results indicated that age of irradiation was a significant factor influencing operant responding, such that older rats tested at similar ages and exposed to similar doses of 56Fe particles showed similar performance decrements. The results are interpreted as indicating that the performance decrement is not a function of age per se, but instead is dependent upon an interaction between the age of irradiation, the age of testing, and exposure to HZE particles. The nature of these effects and how age of irradiation affects cognitive performance after an interval of 15 to 16 months remains to be established.
doi:10.1007/s11357-011-9226-4
PMCID: PMC3260355  PMID: 21424788
56Fe particles; Aging; Cognitive; Behavior; Cosmic rays
2.  Aging modifies brain region-specific vulnerability to experimental oxidative stress induced by low dose hydrogen peroxide 
Age  2007;29(4):191-203.
Our previous studies demonstrated a significant decline in brain function and behavior in Fischer 344 (F344) rats with age. The present study was designed to test the hypothesis that dysregulation in calcium homeostasis (as assessed through 45Ca flux) may contribute to the increase in age-related vulnerability to oxidative stress in brain regions, and result in a deficit in behavior-mediated signaling. Crude membrane (P-2) and more purified synaptosomal fractions were isolated from the striatum, hippocampus, and frontal cortex of young (6 months) and old (22 months) F344 rats and were assessed for calcium flux and extracellular-regulated kinase activity 1 (ERK) under control and oxidative stress conditions induced by low dose hydrogen peroxide (final concentration 5 μM). The level of oxidative stress responses was monitored by measuring reactive oxygen species (ROS) and glutathione (GSH). The results showed a significant difference in oxidative stress responses between young and old rats in evaluated brain regions. Old rats showed higher sensitivity to oxidative stress than young rats. The present findings show the differential effects of oxidative stress on calcium flux in brain regions with age that are dependent upon the brain areas examined and the fraction assessed. The accumulation of ROS and the decrease in GSH in the frontal cortex were sufficient to decrease ERK activity in old rats. This is the first study, to our knowledge, that demonstrates age-related differential sensitivity to oxidative stress expressed as a function of behavior-mediated signaling and stress levels among different fractions isolated from brain regions controlling behavior.
doi:10.1007/s11357-007-9039-7
PMCID: PMC2267029  PMID: 19424838
P-2 fraction; Synaptosomes; Calcium; Glutathione; Extracellular signal-regulated kinase
3.  Introduction 
Age  2005;27(1):3.
doi:10.1007/s11357-005-5197-7
PMCID: PMC3456090
4.  Effect of diet on the disruption of operant responding at different ages following exposure to 56Fe particles 
Age  2005;27(1):69-73.
Rats were exposed to 2.0 Gy of 56Fe particles to study the relationship between age and diet in the heavy particle-induced disruption of performance on an ascending fixed-ratio task. Irradiation produced a disruption of operant responding in rats tested 5 and 8 months after exposure, which was prevented by maintaining the rats on a diet containing strawberry, but not blueberry, extract. When tested 13 and 18 months after irradiation there were no differences in performance between the radiated rats maintained on control, strawberry or blueberry diets. These observations suggest that the beneficial effects of antioxidant diets may be dependent upon the age of testing.
doi:10.1007/s11357-005-4000-0
PMCID: PMC3456091  PMID: 23598605
antioxidant; behaviors; radiation; vision
5.  Dietary supplementation with fruit polyphenolics ameliorates age-related deficits in behavior and neuronal markers of inflammation and oxidative stress 
Age  2005;27(1):49-57.
Dietary supplementation with fruit or vegetable extracts can ameliorate age-related declines in measures of learning, memory, motor performance, and neuronal signal transduction in a rat model. To date, blueberries have proved most effective at improving measures of motor performance, spatial learning and memory, and neuronal functioning in old rats. In an effort to further characterize the bioactive properties of fruits rich in color and correspondingly high in anthocyanins and other polyphenolics, 19-month-old male Fischer rats were fed a well-balanced control diet, or the diet supplemented with 2% extract from either blueberry, cranberry, blackcurrant, or Boysenberry fruit for eight weeks before testing began. The blackcurrant and cranberry diets enhanced neuronal signal transduction as measured by striatal dopamine release, while the blueberry and cranberry diets were effective in ameliorating deficits in motor performance and hippocampal HSP70 neuroprotection; these changes in HSP70 were positively correlated with performance on the inclined screen. It appears that the polyphenols in blueberries and cranberries have the ability to improve muscle tone, strength and balance in aging rats, whereas polyphenols in blueberries, cranberries and blackcurrants have the ability to enhance neuronal functioning and restore the brain’s ability to generate a neuroprotective response to stress.
doi:10.1007/s11357-005-4004-9
PMCID: PMC3456098  PMID: 23598603
anthocyanins; antioxidant; cognition; HPS70; memory; motor performance

Results 1-5 (5)