Brain norepinephrine changes with simulated weightlessness and relation to exercise training
| Autor: | Mark S. Sothmann, Gary M. Kastello |
|---|---|
| Rok vydání: | 1999 |
| Předmět: |
Male
medicine.medical_specialty medicine.medical_treatment Experimental and Cognitive Psychology Physical exercise Norepinephrine (medication) Head-Down Tilt Rats Sprague-Dawley Behavioral Neuroscience chemistry.chemical_compound Norepinephrine Deconditioning Stress Physiological Internal medicine medicine Animals Chronic stress Neurotransmitter Saline Weightlessness Simulation Analysis of Variance Cardiovascular Deconditioning Brain Exercise Therapy Rats Disease Models Animal Endocrinology chemistry Physical Fitness Catecholamine Locus coeruleus Weightlessness Countermeasures General Adaptation Syndrome medicine.drug |
| Zdroj: | Physiologybehavior. 66(5) |
| ISSN: | 0031-9384 |
| Popis: | Maintenance of nervous system function during periods of a deconditioning syndrome is important to prevent diminished psychological/behavioral, and physiological function observed during periods of bed rest, physical inactivity, and weightlessness. A main neurotransmitter is norepinephrine (NE), and its regulation yields insight into nervous system function. This research tested the hypotheses that, 1) deconditioning syndrome induced by simulated weightlessness of 9 days via the head-down tilt (HDT) model results in a blunted noradrenergic turnover rate in selected brain tissue and, 2) that exercise training acts as a countermeasure for these changes in noradrenergic activity. Male Sprague-Dawley rats (3 months, n = 60) were divided into either a HDT (HDT, n = 20), cage control (CAGE-CN, n = 20) or an exercise trained HDT (HDT-EX, n = 20) group. Each group was further subdivided into a saline (n = 10) or alpha-methyl-tyrosine (AM, n = 10) (200 mg/kg) injected subgroup. Animals in the HDT groups were tail suspended in a 30 degrees head-down tilt position for 9 days. Norepinephrine turnover was determined 3 h following administration of saline or alpha-methyl-para-tyrosine. The NE turnover rate (ng gm(-1) x h(-1)) for the CN, HDT, and HDT-EX groups, respectively, were as follows: locus coeruleus, 63 +/- 33, *134 +/- 65, 85 +/- 61; hypothalamus, 195 +/- 50, *47 +/- 47; *93 +/- 34; cerebellum, 10 +/- 18, *65 +/- 15, *53 +/- 19; cerebral cortex, 6 +/- 20, *28 +/- 15, *68 +/- 22. (*Denotes significant difference from the control group at the por = 0.05 level of significance; +denotes significant difference from the HDT group at the por = 0.05 level of significance.) These findings suggest that: 1) norepinephrine turnover rate adapts in a tissue-specific manner following a 9-day tail suspension, 2) increased norepinephrine turnover rates and norepinephrine tissue content in the HDT group are consistent with neural adaptation to a chronic stress response. |
| Databáze: | OpenAIRE |
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