Regulation of the ion-transporting mitochondrion-rich cell during adaptation of teleost fishes to different salinities.
The mitochondrion-rich cells (MRCs) in teleost gill and equivalent tissues are important osmoregulatory sites in maintaining ionic balance. These cells express a variety of ion pumps, transporters, and channels, which play central roles in ionic regulation. Recently, two types of MRCs have been identified in euryhaline fishes: seawater (SW)-type MRCs extrude Na and Cl ions in SW conditions; freshwater (FW)-type MRCs take up at least Cl-. Long-term development/differentiation of the two types of MRCs during adaptation to different salinities appears to be regulated mainly by endocrine factors. Osmolality, Ca2+, neurotransmitters, and fast-acting hormones rapidly regulate the SW MRCs. Recent information is assembled in this review and suggests the functional plasticity of highly specialized MRCs.
Sakamoto
T
T
Faculty of Integrated Arts and Sciences, Hiroshima University, Higashi-hiroshima 739-8521, Japan. tatsuyas@hiroshima-u.ac.jp
Uchida
K
K
Yokota
S
S
D000222:Adaptation, Physiological; D000818:Animals; D001692:Biological Transport / Q000502:physiology; D002118:Calcium / Q000378:metabolism; D005399:Fishes / Q000378:metabolism / Q000502:physiology*; D005618:Fresh Water; D005880:Gills / Q000166:cytology / Q000378:metabolism*; D008928:Mitochondria / Q000502:physiology*; D009994:Osmolar Concentration; D012623:Seawater; D012965:Sodium Chloride / Q000378:metabolism; D014882:Water-Electrolyte Balance / Q000502:physiology*
D012965:Sodium Chloride; D002118:Calcium