| Autor: |
Kolb, E. M., Kelly, S. A., Middleton, K. M., Sermsakdi, L. S., Chappell, M. A., Garland Jr., T. |
| Předmět: |
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| Zdroj: |
Journal of Experimental Biology; Feb2010, Vol. 213 Issue 3, p510-519, 10p, 4 Charts, 2 Graphs |
| Abstrakt: |
Voluntary activity is a complex trait, comprising both behavioral (motivation, reward) and anatomical/physiological (ability) elements. In the present study, oxygen transport was investigated as a possible limitation to further increases in running by four replicate lines of mice that have been selectively bred for high voluntary wheel running and have reached an apparent selection limit. To increase oxygen transport capacity, erythrocyte density was elevated by the administration of an erythropoietin (EPO) analogue. Mice were given two EPO injections, two days apart, at one of two dose levels (100 or 300μg kg-1). Hemoglobin concentration ([Hb]), maximal aerobic capacity during forced treadmill exercise (V̇O2,max ) and voIuntary wheel running were measured. [Hb] did not differ between high runner (HR) and non-selected control (C) lines without EPO treatment. Both doses of EPO significantly (P<0.0001) increased [Hb] as compared with sham-injected animals, with no difference in [Hb] between the 100μgkg-1 and 300 μg kg-1 dose levels (overall mean of 4.5gdl-1 increase). EPO treatment significantly increased V̇O2,max by -5% in both the HR and C lines, with no dose X line type interaction. However, wheel running (revolutions per day) did not increase with EPO treatment in either the HR or C lines, and in fact significantly decreased at the higher dose in both line types. These results suggest that neither [Hb] per se nor V̇O2,max is limiting voluntary wheel running in the HR lines. Moreover, we hypothesize that the decrease in wheel running at the higher dose of EPO may reflect direct action on the reward pathway of the brain. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
| Externí odkaz: |
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