Journal
AMERICAN JOURNAL OF PHYSIOLOGY-REGULATORY INTEGRATIVE AND COMPARATIVE PHYSIOLOGY
Volume 294, Issue 4, Pages R1347-R1355Publisher
AMER PHYSIOLOGICAL SOC
DOI: 10.1152/ajpregu.00687.2007
Keywords
proton; exercise; pain; gender; sex; testosterone; estrogen
Categories
Funding
- NIAMS NIH HHS [R01 AR052316-03, R01 AR053509, R01 AR053509-01A1, R01 AR053509-03, R01 AR052316, AR-053509, R01 AR052316-04, AR-052316, R01 AR052316-02, R01 AR053509-02, R01 AR052316-01A1] Funding Source: Medline
Ask authors/readers for more resources
Muscle fatigue is associated with a number of clinical diseases, including chronic pain conditions. Decreases in extracellular pH activates acid-sensing ion channel 3 (ASIC3), depolarizes muscle, protects against fatigue, and produces pain. We examined whether ASIC3-/- mice were more fatigable than ASIC3-/- mice in a task-dependent manner. We developed two exercise protocols to measure exercise-induced muscle fatigue: (fatigue task 1, three 1-h runs; fatigue task 2, three 30-min runs). In fatigue task 1, male ASIC3-/- mice muscle showed less fatigue than male ASIC3-/- mice and female ASIC3+/- mice. No differences in fatigue were observed in fatigue task 2. We then tested whether the development of muscle fatigue was dependent on sex and modulated by testosterone. Female ASIC3-/- mice that were ovariectomized and administered testosterone developed less muscle fatigue than female ASIC3-/- mice and behaved similarly to male ASIC3-/- mice. However, testosterone was unable to rescue the muscle fatigue responses in ovariectomized ASIC3-/- mice. Plasma levels of testosterone from male ASIC3-/- mice were significantly lower than in male ASIC3-/- mice and were similar to female ASIC3+/+ mice. Muscle fiber types, measured by counting ATPase-stained whole muscle sections, were similar in calf muscles from male and female ASIC3+/+ mice. These data suggest that both ASIC3 and testosterone are necessary to protect against muscle fatigue in a task-dependent manner. Also, differences in expression of ASIC3 and the development of exercise-induced fatigue could explain the female predominance in clinical syndromes of pain that include muscle fatigue.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available