Insights from venous oxygen profiles: oxygen utilization and management in diving California sea lions
Insights from venous oxygen profiles: oxygen utilization and management in diving California sea lions
复制标题
DOI：
10.1242/jeb.085985
复制
发表时间：
2013-09-01
影响因子：
2.8
通讯作者：
Ponganis, Paul J.
中科院分区：
文献类型：
--
作者：
McDonald, Birgitte I.;Ponganis, Paul J.
O-2 储存的管理和消耗是海洋哺乳动物有氧潜水能力的基础。加州海狮 (Zalophus californianus) 可能会在所有潜水过程中优化 O-2 储存管理，但在深潜至 300 米以上深度时会接近其生理极限。血液 O-2 是成年海狮体内 O-2 储存量的最大组成部分。因此，我们研究了加州海狮在母体出海觅食期间潜水期间的静脉血 O-2 消耗情况，方法是：(1) 记录潜水期间 O-2 静脉分压 (PO2) 曲线，(2) 表征海狮 Hb 的 O-2-血红蛋白 (Hb) 解离曲线，(3) 使用解离曲线将 PO2 曲线转换为 Hb 饱和度百分比 (SO2) 曲线。 O-2-Hb 解离曲线是其他鳍足类动物的典型曲线（P-50=28 +/- 2mmHg，pH 7.4）。在 43% 的潜水中，初始静脉 SO2 值大于 78%（估计静息静脉 SO2），表明静脉血已动脉化。在常规浅潜水期间，血液 O-2 远未耗尽，最低静脉 SO2 值通常大于 50%。然而，在持续时间超过 4 分钟的深潜中，静脉 SO2 在潜水结束前达到低于 5% 的最小值，但随后在上升的最后 30-60 秒内增加。这些深潜曲线与短暂的静脉血 O-2 消耗一致，随后在上升过程中通过肺气体交换和外周血流部分恢复静脉 O-2。海狮浅潜和深潜之间静脉 O-2 分布的这些差异反映了 O-2 储存管理的不同策略，并表明潜在的心血管反应也会有所不同。
The management and depletion of O-2 stores underlie the aerobic dive capacities of marine mammals. The California sea lion (Zalophus californianus) presumably optimizes O-2 store management during all dives, but approaches its physiological limits during deep dives to greater than 300. m depth. Blood O-2 comprises the largest component of total body O-2 stores in adult sea lions. Therefore, we investigated venous blood O-2 depletion during dives of California sea lions during maternal foraging trips to sea by: (1) recording venous partial pressure of O-2 (PO2) profiles during dives, (2) characterizing the O-2-hemoglobin (Hb) dissociation curve of sea lion Hb and (3) converting the PO2 profiles into percent Hb saturation (SO2) profiles using the dissociation curve. The O-2-Hb dissociation curve was typical of other pinnipeds (P-50=28 +/- 2mmHg at pH 7.4). In 43% of dives, initial venous SO2 values were greater than 78% (estimated resting venous SO2), indicative of arterialization of venous blood. Blood O-2 was far from depleted during routine shallow dives, with minimum venous SO2 values routinely greater than 50%. However, in deep dives greater than 4. min in duration, venous SO2 reached minimum values below 5% prior to the end of the dive, but then increased during the last 30-60s of ascent. These deep dive profiles were consistent with transient venous blood O-2 depletion followed by partial restoration of venous O-2 through pulmonary gas exchange and peripheral blood flow during ascent. These differences in venous O-2 profiles between shallow and deep dives of sea lions reflect distinct strategies of O-2 store management and suggest that underlying cardiovascular responses will also differ.