Center for Marine Biotechnology and Biomedicine, Scripps Institution of Oceanography, University of California San Diego, La Jolla, CA 92093-0204, USA.
J Exp Biol. 2011 Jun 1;214(Pt 11):1802-12. doi: 10.1242/jeb.052233.
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.
有氧潜水极限（ADL）的生理基础是肌肉氧气（O2）储备的消耗，这与潜水后血乳酸升高的开始有关。研究人员开发了一种双波长近红外分光光度计，并用于测量帝企鹅（Aptenodytes forsteri）在潜水过程中运动肌肉中的肌红蛋白（Mb）O2饱和度水平。观察到两种不同的肌肉 O2 消耗模式。A型潜水呈单调下降，在接近 ADL 的潜水时，肌肉 O2 储备几乎完全耗尽。这种 Mb 去饱和度模式与肌肉血流缺乏一致，支持了潜水后血乳酸积累的开始是由于潜水过程中肌肉 O2 消耗的假设。A型 Mb 去饱和度的平均速率允许根据 Mb 浓度为 6.4 g 100 g-1 肌肉计算出平均肌肉 O2 消耗为 12.4 ml O2 kg-1 肌肉 min-1。B 型去饱和度模式显示出更渐进的下降，通常在 Mb 去饱和度达到潜水中期的平台。这个潜水中期的平台表明在这些潜水过程中肌肉灌注得到了维持。在 B 型潜水结束时，Mb 去饱和度速率增加，并且在 ADL 之外的潜水时，Mb 饱和度通常达到近 0%。因此，尽管帝企鹅潜水可能使用不同的生理策略，但两种 Mb 去饱和度模式都支持这样的假设，即潜水后乳酸积累的开始是由于肌肉 O2 储备的消耗。
