Monitoring of Na+/K+-ATPase mRNA expression in the cinnamon clownfish, Amphiprion melanopus, exposed to an osmotic stress environment: profiles on the effects of exogenous hormone

Abstract

We examined changes in the expression of Na ? /K ? -ATPase mRNA in the gills of the cinnamon clownfish using quantitative real-time PCR in an osmotically changing environment [seawater (35 psu; practical salinity unit, 1 psu & 1%) ? brackish water (17.5 psu) and brackish water with prolactin]. The expression of Na ? / K ? -ATPase mRNA in gills was increased after the transfer to brackish water, and the expression was repressed by prolactin treatment. Also, activities of gill Na ? /K ? -ATPase and plasma cortisol levels increased after the transfer to brackish water and were repressed in brackish water with prolactin treatment. Na ? /K ? -ATPase-immunoreactive cells were almost consistently observed in the gill filaments, but absent from the lamella epithelia. The plasma osmolality level decreased in brackish water, but the level of this parameter increased in brackish water with prolactin treatment during salinity change. These results suggest that the Na ? /K ? -ATPase gene plays an important role in osmoregulation in gills, and prolactin improves the hyperosmoregulatory ability of cinnamon clownfish in a brackish water (hypoosmotic) environment.

Effect of hypo-osmotic environmental changes on the expression of gonadotropin-releasing hormone, its receptor, and gonadotropin hormone subunit mRNA in adult chum salmon (Oncorhynchus keta)

“…The level of osmolality decreased when anadromous adult chum salmon were transferred to an artificially hypo-osmotic environment (Table 2), supporting findings from other studies that have investigated the effect of exposure to hypo-osmotic conditions on various fish species, including chum salmon (Hirano et al 1987), black porgy (Acanthopagrus schlegeli; An et al 2008), and cinnamon clownfish (Amphiprion melanopus; Park et al 2011). This observed decline in osmolality may result from the osmoregulation of water inflow and ion outflow from the body (An et al 2008;Park et al 2011).…”

“…This observed decline in osmolality may result from the osmoregulation of water inflow and ion outflow from the body (An et al 2008;Park et al 2011).…”