Clifford Alexander M, Zimmer Alex M, Wood Chris M, Goss Greg G
Department of Biological Sciences, University of Alberta, 116 St. and 85 Ave., Edmonton, AB, Canada T6G 2R3 Bamfield Marine Sciences Centre, 100 Pachena Rd, Bamfield, BC, Canada V0R 1B0
Bamfield Marine Sciences Centre, 100 Pachena Rd, Bamfield, BC, Canada V0R 1B0 Department of Zoology, University of British Columbia, Vancouver, BC, Canada V6T 1Z4.
J Exp Biol. 2016 Sep 15;219(Pt 18):2814-2818. doi: 10.1242/jeb.141598. Epub 2016 Jul 8.
Hagfish skin has been reported as an important site for ammonia excretion and as the major site of systemic oxygen acquisition. However, whether cutaneous O uptake is the dominant route of uptake remains under debate; all evidence supporting this hypothesis has been derived using indirect measurements. Here, we used partitioned chambers and direct measurements of oxygen consumption and ammonia excretion to quantify cutaneous and branchial exchanges in Pacific hagfish (Eptatretus stoutii) at rest and following exhaustive exercise. Hagfish primarily relied on the gills for both O uptake (81.0%) and ammonia excretion (70.7%). Following exercise, both O uptake and ammonia excretion increased, but only across the gill; cutaneous exchange was not increased. When branchial O availability was reduced by exposure to anteriorly localized hypoxia (∼4.6 kPa O), cutaneous O consumption was only slightly elevated on an absolute basis. These results refute a major role for cutaneous O acquisition in the Pacific hagfish.
有报道称盲鳗的皮肤是氨排泄的重要部位，也是全身获取氧气的主要部位。然而，皮肤对氧气的摄取是否是主要的摄取途径仍存在争议；所有支持这一假设的证据都是通过间接测量得出的。在这里，我们使用分隔的实验箱，直接测量氧气消耗和氨排泄，以量化太平洋盲鳗（Eptatretus stoutii）在静息状态和力竭运动后的皮肤和鳃的气体交换情况。盲鳗主要依靠鳃来摄取氧气（81.0%）和排泄氨（70.7%）。运动后，氧气摄取和氨排泄都增加了，但仅通过鳃增加；皮肤气体交换没有增加。当通过暴露于前部局部缺氧（约4.6 kPa氧气）来降低鳃的氧气供应时，皮肤的氧气消耗仅在绝对值上略有升高。这些结果反驳了皮肤摄取氧气在太平洋盲鳗中起主要作用的观点。
