Flexible ammonia handling strategies using both cutaneous and branchial epithelia in the highly ammonia tolerant Pacific hagfish.
Flexible ammonia handling strategies using both cutaneous and branchial epithelia in the highly ammonia tolerant Pacific hagfish.
复制标题
利用高度氨耐受太平洋盲鳗的皮肤和鳃上皮的灵活的氨处理策略。
DOI：
10.1152/ajpregu.00351.2016
复制
发表时间：
2017
期刊：
影响因子：
--
通讯作者：
Goss, Greg G
中科院分区：
文献类型：
--
作者：
Clifford, Alexander M;Weinrauch, Alyssa M;Edwards, Susan L;Wilkie, Michael P;Goss, Greg G
盲鳗消耗腐肉，可能使它们暴露于缺氧，高碳酸血症和高环境氨（HEA）。我们调查了鳃和皮肤氨处理策略，太平洋盲鳗（Eptatretus stoutii）容忍和恢复高氨负荷。将盲鳗暴露于HEA（20 mmol/l）48 h，以升高血浆总氨（TAmm）水平，然后置于无氨海水中4 h恢复期的分隔室中，其中在前室和后室中独立测量氨排泄（JAmm）。还通过使盲鳗在前室或后室中经受HEA来进行局部HEA暴露。在恢复过程中，HEA暴露的动物增加了两个室的JAmm，后室占总JAmm的约20%，而非HEA暴露的鱼约为11%。当整条盲鳗和尾区暴露于HEA时，血浆TAmm显著增加。另外，血浆TAmmdidn’t升高后，前部局部HEA exposed. JAmmdidn’t浓度依赖性（0.05-5 mmol/l）在整个切除的皮肤补丁高达8倍以上的速度比在皮肤切片，从HEA暴露的盲鳗切除。越靠后部位切除的皮肤JAmm越大。免疫组织化学用盲鳗特异性抗恒河猴糖蛋白c型（α-hRhcg;氨转运蛋白）抗体通过在盲鳗表皮的基底面染色来表征，而蛋白质印迹法证明Rhcg在更后部的皮肤切片中表达更高。我们的结论是，皮肤Rhcg蛋白参与皮肤氨排泄太平洋盲鳗，这种机制可能是特别重要的喂养过程中。
Hagfish consume carrion, potentially exposing them to hypoxia, hypercapnia, and high environmental ammonia (HEA). We investigated branchial and cutaneous ammonia handling strategies by which Pacific hagfish (Eptatretus stoutii) tolerate and recover from high ammonia loading. Hagfish were exposed to HEA (20 mmol/l) for 48 h to elevate plasma total ammonia (TAmm) levels before placement into divided chambers for a 4-h recovery period in ammonia-free seawater where ammonia excretion (JAmm) was measured independently in the anterior and posterior compartments. Localized HEA exposures were also conducted by subjecting hagfish to HEA in either the anterior or posterior compartments. During recovery, HEA-exposed animals increasedJAmmin both compartments, with the posterior compartment comprising ~20% of the totalJAmmcompared with ~11% in non-HEA-exposed fish. Plasma TAmmincreased substantially when whole hagfish and the posterior regions were exposed to HEA. Alternatively, plasma TAmmdid not elevate after anterior localized HEA exposure.JAmmwas concentration dependent (0.05–5 mmol/l) across excised skin patches at up to eightfold greater rates than in skin sections that were excised from HEA-exposed hagfish. Skin excised from more posterior regions displayed greaterJAmmthan those from more anterior regions. Immunohistochemistry with hagfish-specific anti-rhesus glycoprotein type c (α-hRhcg; ammonia transporter) antibody was characterized by staining on the basal aspect of hagfish epidermis while Western blotting demonstrated greater expression of Rhcg in more posterior skin sections. We conclude that cutaneous Rhcg proteins are involved in cutaneous ammonia excretion by Pacific hagfish and that this mechanism could be particularly important during feeding.