Adaptive features of skeletal muscles of mole rats (Spalax ehrenbergi) to intensive activity under subterranean hypoxic conditions.
Mole rats of the Spalax ehrenbergi superspecies are blind subterranean rodents that live under fluctuating oxygen supply, reduced to a measured 6% O(2), and mostly probably lower, during the rainy season. Fiber typing of muscles of the neck (trapezius) and leg (gastrocnemius, quadriceps) using standard histochemical techniques (succinic dehydrogenase, myosin ATPase) showed that the muscle fibers of mole rats in natural settings, as well as after extended captivity, were predominantly type IIa. The same muscles in laboratory rats showed the full range of fiber types. In contrast, the hearts of the mole rats and the laboratory rats were very similar. Our results indicate that skeletal muscle in the mole rats appears to have evolved in response to specific environmental demands to permit intensive endurance burrowing activities under conditions of severe or chronic hypoxia.
Avivi
Aaron
A
Laboratory of Molecular Evolution of Animals, Institute of Evolution, Haifa University, Mount Carmel, Haifa 31905, Israel. aaron@research.haifa.ac.il
Band
Mark
M
Joel
Alma
A
Shenzer
Pessia
P
Coleman
Raymond
R
D000818:Animals; D000860:Hypoxia / Q000503:physiopathology*; D019577:Mole Rats; D009043:Motor Activity / Q000502:physiology*; D018485:Muscle Fibers, Skeletal / Q000166:cytology / Q000378:metabolism; D018482:Muscle, Skeletal / Q000166:cytology / Q000378:metabolism*; D009218:Myosins / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D013385:Succinate Dehydrogenase / Q000378:metabolism
D013385:Succinate Dehydrogenase; D009218:Myosins