Wilkie M P, Bradshaw P G, Joanis V, Claude J F, Swindell S L
Department of Biology, Mount Allison University, Sackville, New Brunswick E4L 1G7, Canada.
Physiol Biochem Zool. 2001 Mar-Apr;74(2):261-72. doi: 10.1086/319656.
Although the majority of the sea lamprey's (Petromyzon marinus) life cycle is spent as a burrow-dwelling larva, or ammocoete, surprisingly little is known about intermediary metabolism in this stage of the lamprey's life history. In this study, larval sea lampreys (ammocoetes) were vigorously exercised for 5 min, and their patterns of metabolic fuel depletion and replenishment and oxygen consumption, along with measurements of net whole-body acid and ion movements, were followed during a 4-24-h postexercise recovery period. Exercise led to initial five- to sixfold increases in postexercise oxygen consumption, which remained significantly elevated by 1.5-2.0 times for the next 3 h. Exercise also led to initial 55% drops in whole-body phosphocreatine, which was restored by 0.5 h, but no significant changes in whole-body adenosine triphosphate were observed. Whole-body glycogen concentrations dropped by 70% immediately following exercise and were accompanied by a simultaneous ninefold increase in lactate. Glycogen and lactate were quickly restored to resting levels after 0.5 and 2.0 h, respectively. The presence of an associated metabolic acidosis was supported by very high rates of metabolic acid excretion, which approached 1,000 nmol g(-1) during the first 2 h of postexercise recovery. Exercise-induced ion imbalances were also rapidly alleviated, as initially high rates of net Na(+) and Cl(-) loss (-1,200 nmol g(-1) h(-1) and -1,800 nmol g(-1) h(-1), respectively) were corrected within 1-2 h. Although larval sea lampreys spend most of their time burrowed, they are adept at performing and recovering from vigorous anaerobic exercise. Such attributes could be important when these animals are vigorously swimming or burrowing as they evade predators or forage.
虽然海七鳃鳗（Petromyzon marinus）生命周期的大部分时间是以穴居幼体，即沙隐虫的形态度过的，但令人惊讶的是，对于七鳃鳗生命史这一阶段的中间代谢情况却知之甚少。在本研究中，对海七鳃鳗幼体（沙隐虫）进行了5分钟的剧烈运动，并在运动后4 - 24小时的恢复期内，追踪其代谢燃料消耗与补充模式、耗氧量，以及全身净酸和离子移动的测量情况。运动导致运动后耗氧量最初增加了五到六倍，在接下来的3小时内仍显著升高1.5 - 2.0倍。运动还导致全身磷酸肌酸最初下降了55%，0.5小时后恢复，但未观察到全身三磷酸腺苷有显著变化。运动后全身糖原浓度立即下降了70%，同时乳酸增加了九倍。糖原和乳酸分别在0.5小时和2.0小时后迅速恢复到静息水平。运动后极高的代谢酸排泄率支持了相关代谢性酸中毒的存在，在运动后恢复的最初2小时内，代谢酸排泄率接近1000 nmol g(-1)。运动引起的离子失衡也迅速得到缓解，最初较高的净Na(+)和Cl(-)损失率（分别为-1200 nmol g(-1) h(-1)和-1800 nmol g(-1) h(-1)）在1 - 2小时内得到纠正。虽然海七鳃鳗幼体大部分时间都在洞穴中，但它们擅长进行剧烈的无氧运动并从中恢复。当这些动物为躲避捕食者或觅食而剧烈游泳或挖掘洞穴时，这些特性可能很重要。
