title: Osmoregulatory adaptations of freshwater air-breathing snakehead fish (Channa striata) after exposure to brackish water.
abstract: NaCl-rich rock salt dissolved in natural water source leads to salinity fluctuation that profoundly affects freshwater ecosystem and aquatic fauna. The snakehead (Channa striata) can live in saline water, but the osmoregulatory mechanisms underlying this ability remain unclear. Herein, we found that exposure to salinities ≥ 10‰ NaCl markedly elevated plasma cortisol and glucose levels, and caused muscle dehydration. In a study of time-dependent response after being transferred from fresh water (0‰ NaCl, FW) to salt-dissolved brackish water (10‰ NaCl, SW), FW-SW, cortisol increased rapidly along with elevations of plasma glucose and lactate. Interestingly, plasma cortisol returned to baseline after prolonged exposure, followed by a second peak that probably enhanced the branchial Na(+)/K(+)-ATPase activity. Under SW-FW condition, Na(+)/K(+)-ATPase activity was not altered as compared to SW-adapted fish. In conclusion, salinity change, especially FW-SW, induced a stress response and hence cortisol release in C. striata, which might increase plasma glucose and lactate to energize the branchial Na(+)/K(+)-ATPase.
authors.affiliation: Department of Biology, Faculty of Science, Khon Kaen University, Khon Kaen, 40002, Thailand, laiana@kku.ac.th.
authors.forename: La-iad
authors.initials: LI
authors.lastname: Nakkrasae
authors.forename: Khanitha
authors.initials: K
authors.lastname: Wisetdee
authors.forename: Narattaphol
authors.initials: N
authors.lastname: Charoenphandhu
mesh_terms: D000220:Adaptation, Biological / Q000502:physiology*; D000704:Analysis of Variance; D000818:Animals; D001774:Blood Chemical Analysis; D001786:Blood Glucose / Q000378:metabolism; D002713:Chlorine / Q000097:blood; D005618:Fresh Water; D006854:Hydrocortisone / Q000097:blood; D009994:Osmolar Concentration; D064587:Osmoregulation / Q000502:physiology*; D010473:Perciformes / Q000502:physiology*; D011188:Potassium / Q000097:blood; D011804:Quinolines; D000068357:Saline Waters; D054712:Salinity; D012964:Sodium / Q000097:blood; D000254:Sodium-Potassium-Exchanging ATPase / Q000378:metabolism; D013312:Stress, Physiological / Q000502:physiology*; D013785:Thailand; D013997:Time Factors
chemical_list: D001786:Blood Glucose; D011804:Quinolines; D002713:Chlorine; D012964:Sodium; C047117:bicinchoninic acid; D000254:Sodium-Potassium-Exchanging ATPase; D011188:Potassium; D006854:Hydrocortisone