期刊
JOURNAL OF EXPERIMENTAL BIOLOGY
卷 214, 期 11, 页码 1802-1812出版社
COMPANY OF BIOLOGISTS LTD
DOI: 10.1242/jeb.052233
关键词
diving; myoglobin; emperor penguin; muscle; oxygen store; NIR; aerobic dive limit; ADL; metabolic rate; O-2 consumption
类别
资金
- NSF [OPP 0229638, 0538594, 0944220]
- NIH
- UC
- Los Angeles Achievement Rewards for College Scientists fellowship
- Philanthropic Educational Organization
- Office of Polar Programs (OPP)
- Directorate For Geosciences [0944220] Funding Source: National Science Foundation
- Office of Polar Programs (OPP)
- Directorate For Geosciences [0538594] Funding Source: National Science Foundation
The physiological basis of the aerobic dive limit (ADL), the dive duration associated with the onset of post-dive blood lactate elevation, is hypothesized to be depletion of the muscle oxygen (O-2) store. A dual wavelength near-infrared spectrophotometer was developed and used to measure myoglobin (Mb) O-2 saturation levels in the locomotory muscle during dives of emperor penguins (Aptenodytes forsteri). Two distinct patterns of muscle O-2 depletion were observed. Type A dives had a monotonic decline, and, in dives near the ADL, the muscle O-2 store was almost completely depleted. This pattern of Mb desaturation was consistent with lack of muscle blood flow and supports the hypothesis that the onset of post-dive blood lactate accumulation is secondary to muscle O-2 depletion during dives. The mean type A Mb desaturation rate allowed for calculation of a mean muscle O-2 consumption of 12.4. ml O-2. kg(-1) muscle. min(-1), based on a Mb concentration of 6.4. g 100. g(-1) muscle. Type B desaturation patterns demonstrated a more gradual decline, often reaching a mid-dive plateau in Mb desaturation. This mid-dive plateau suggests maintenance of some muscle perfusion during these dives. At the end of type B dives, Mb desaturation rate increased and, in dives beyond the ADL, Mb saturation often reached near 0%. Thus, although different physiological strategies may be used during emperor penguin diving, both Mb desaturation patterns support the hypothesis that the onset of post-dive lactate accumulation is secondary to muscle O-2 store depletion.
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