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Short-term effects of hyposmotic shock on Na+/K+-ATPase expression in gills of the euryhaline milkfish, Chanos chanos
- Source :
- Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology. 143:406-415
- Publication Year :
- 2006
- Publisher :
- Elsevier BV, 2006.
-
Abstract
- Changes in expression of gill Na+/K+ -ATPase (NKA) on a short-term (96 h) time-course following hyposmotic shock (direct transfer to fresh water) of the euryhaline, marine milkfish were studied on gene, protein, and cell levels in this paper. Plasma osmolality and [Na+] responded with rapid declines in 3 h post-transfer yet, thereafter, remained constant. Plasma [Cl-] gradually fell to a significantly lower level at 6 h post-transfer. Gills responded to hyposmotic shock by a dual phase enhancement of NKA activity and protein abundance; (a) Before 24 h: NKA activity increased as early as 3 h and reached a maximum level from 6 to 12 h post-transfer coincided with the sustained lower levels of plasma osmolality, [Na+], and [Cl-] since 3 h post-transfer. This was followed by a gradual rise in alpha-subunit protein levels that peaked at 12 h post-transfer. Meanwhile, alpha-mRNA of NKA did no show significant change. (b) After 24 h: NKA activity as well as the amounts of alpha-subunit mRNA and protein increased significantly. Direct freshwater transfer induced a prompt and significant decrease of NKA immunoreactive (NKIR) cell abundance in filaments before 24 h, followed by a significant increase after 24 h due to their development in filaments and lamellae. Increased number of NKIR cells after 24 h of hyposmotic shock may occur in conjunction with rise of NKA activity as well as alpha-subunit mRNA and protein abundance. In conclusion, milkfish is able to avoid an excessive drop in plasma ions immediately upon hyposmotic shock and maintain plasma ions on a marginal lower level in fresh water. Notably, the initial increase in NKA activity (adjustive phase; 3-12 h) and delayed increase in NKA mRNA and protein abundance (regulatory phase; 48-96 h) indicate the importance of a higher level of the gill enzyme in milkfish upon hyposmotic shock.
- Subjects :
- Gills
Gill
medicine.medical_specialty
Physiology
ATPase
Immunoblotting
Fresh Water
Polymerase Chain Reaction
Biochemistry
Osmotic Pressure
Internal medicine
medicine
Animals
Osmotic pressure
Seawater
Na+/K+-ATPase
Molecular Biology
biology
Osmolar Concentration
Sodium
Fishes
Anatomy
Euryhaline
respiratory system
biology.organism_classification
Plasma osmolality
Endocrinology
Milkfish
Shock (circulatory)
biology.protein
Sodium-Potassium-Exchanging ATPase
medicine.symptom
Subjects
Details
- ISSN :
- 10956433
- Volume :
- 143
- Database :
- OpenAIRE
- Journal :
- Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology
- Accession number :
- edsair.doi.dedup.....f7a8589f3e51ff07b90b0b168423ffb9