AUTHOR=Aruna Adimoolam , Wang Tsan-Ping , Cao Jyun-Cing , Lan Dan-Suei , Nagarajan Ganesan , Chang Ching-Fong 

TITLE=Differential Expression of Hypothalamic and Gill-crh System With Osmotic Stress in the Euryhaline Black Porgy, Acanthopagrus schlegelii

JOURNAL=Frontiers in Physiology

VOLUME=12

YEAR=2021

URL=https://www.frontiersin.org/journals/physiology/articles/10.3389/fphys.2021.768122

DOI=10.3389/fphys.2021.768122

ISSN=1664-042X

ABSTRACT=<p>The local gill production of corticotropin releasing hormone (<italic>crh</italic>) and <italic>crh</italic>-receptor (<italic>crhr</italic>) is hypothesized to play important roles during seawater (SW) and freshwater (FW) acclimation in euryhaline black porgy (<italic>Acanthopagrus schlegelii</italic>). The mRNA expression of <italic>crh</italic>, <italic>crhr</italic>, and <italic>Na</italic><sup>+</sup>/<italic>K</italic><sup>+</sup><italic>-ATPase</italic> (<italic>a-nka</italic>) was examined in SW and FW diencephalon (Dien) and in the gills at different exposure time by Q-PCR analysis. The <italic>in situ</italic> hybridization results indicate that <italic>crh</italic> mRNA hybridization signals were more abundant in FW fish in the gigantocellular (PMgc) and parvocellular (PMpc) part of the magnocellular preoptic nucleus versus SW fish. The <italic>crh</italic> and <italic>crhr-</italic>expressing cells were located in basal cells of gill filament. Furthermore, <italic>in vitro</italic> dexamethasone (DEX) treatment could increase the <italic>crh</italic>-system in the gill. Increased transcripts of the <italic>crh</italic>-system in the gill via <italic>in vitro</italic> and <italic>in vivo</italic> CRH treatments suggest that CRH may regulate the system in a local manner. The a-Nka cells were localized in the filament and secondary lamellae mitochondria rich cells (MRCs) of FW fish at 8 h and 1 day. a-Nka cells were seen in both filament and lamellae in the FW but much less in SW fish indicating that gills play key roles in black porgy osmoregulation. Gill <italic>crh</italic> and <italic>crhr</italic> play important roles in the response to salinity stress.</p>