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

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

doi:10.3389/fphys.2021.768122

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

Front Physiol. 2021 Nov 11:12:768122. doi: 10.3389/fphys.2021.768122. eCollection 2021.

Authors

Adimoolam Aruna¹, Tsan-Ping Wang¹, Jyun-Cing Cao¹, Dan-Suei Lan¹, Ganesan Nagarajan^{2

3}, Ching-Fong Chang^{1

3}

Affiliations

¹ Department of Aquaculture, National Taiwan Ocean University, Keelung, Taiwan.
² Department of Basic Sciences, PYD, King Faisal University, Al Hofuf, Saudi Arabia.
³ Center of Excellence for the Oceans, National Taiwan Ocean University, Keelung, Taiwan.

Abstract

The local gill production of corticotropin releasing hormone (crh) and crh-receptor (crhr) is hypothesized to play important roles during seawater (SW) and freshwater (FW) acclimation in euryhaline black porgy (Acanthopagrus schlegelii). The mRNA expression of crh, crhr, and Na ⁺/K ⁺ -ATPase (a-nka) was examined in SW and FW diencephalon (Dien) and in the gills at different exposure time by Q-PCR analysis. The in situ hybridization results indicate that crh 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 crh and crhr-expressing cells were located in basal cells of gill filament. Furthermore, in vitro dexamethasone (DEX) treatment could increase the crh-system in the gill. Increased transcripts of the crh-system in the gill via in vitro and in vivo 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 crh and crhr play important roles in the response to salinity stress.

Keywords: brain; crh; crhr; fish; gill; osmotic stress; α-nka.