Collaborative Research: Oxygen Transport and Utilization During Sleep Apnea in Elephant Seals

该项目将把动物生理学与生物物理学和生物化学结合起来，以检测海象在睡眠期间长时间自发屏气期间从整个动物到亚细胞水平的氧气运输和消耗。这些动物的独特适应包括增强的氧气储存和对心率、血流和组织代谢率的精细调节。这些适应的生理过程和生化机制与组织内氧气转移的基本原理以及海豹和鲸鱼非凡的潜水能力有关。各种微创和非侵入性技术，包括血液/组织采样、血流测量和核磁共振成像/光谱分析，将使这些海豹能够在睡觉时不受干扰地进行研究。这将允许：1)检查这些海豹在10分钟的屏气中对心率、心输出量和肌肉血流量的调节，2)测量整个屏气过程中的血氧耗竭速度，3)随着血氧水平的降低检查血液到肌肉的氧气转移，4)测定肌肉中肌红蛋白的氧去饱和率--肌肉中的储氧蛋白质，5)检查肌肉中的代谢调节，如高能磷酸、磷酸肌酸的耗尽和乳酸的形成，以及6)检查肌肉细胞内肌红蛋白分子的流动性。

This project will combine animal physiology with biophysics and biochemistry in order to examine oxygen transport and consumption from whole animal to subcellular levels during the prolonged, spontaneous breath-holds of elephant seals during sleep. Unique adaptations in these animals include enhanced oxygen storage and exquisite regulation of heart rate, blood flow and tissue metabolic rates. The physiological processes and biochemical mechanisms underlying these adaptations are relevant to the basic principles of oxygen transfer within tissues as well as to the remarkable diving abilities of seals and whales. A variety of minimally- and non-invasive techniques, including blood/tissue sampling, blood flow measurements, and nuclear magnetic resonance imaging/spectroscopy, will allow study of these seals while they sleep undisturbed. This will allow: 1) examination of the regulation of heart rate, cardiac output and muscle blood flow throughout the ten-minute breath-holds of these seals, 2) measurement of the rate of blood oxygen depletion throughout the breath-hold, 3) examination of blood-to-muscle oxygen transfer as the blood oxygen level decreases, 4) determination of the oxygen desaturation rate of myoglobin - the oxygen storage protein in muscle, 5) examination of metabolic regulation in muscle, as reflected in the depletion of the high-energy phosphate, phosphocreatine, and the formation of lactate, and 6) examination of the mobility of the myoglobin molecule within the muscle cell.