Lindane differently modulates intracellular calcium levels in two populations of rainbow trout (Oncorhynchus mykiss) immune cells: head kidney phagocytes and peripheral blood leucocytes.
We studied the in vitro effects of high concentrations of the insecticide lindane (from 2.5 to 100 microM) on intracellular calcium levels ([Ca(2+)](i)) in rainbow trout head kidney phagocytes and peripheral blood leucocytes (PBLs). [Ca(2+)](i) was measured during 6 min by spectrofluorimetry using Indo-1/AM as fluorescent probe. Lindane, from 5 to 100 microM, increased [Ca(2+)](i) in PBLs and from 25 microM in phagocytes. In Ca(2+)-free medium, only 50 and 100 microM lindane increased significantly [Ca(2+)](i) in PBLs and only 100 microM lindane in phagocytes. However, lindane at 5 and 10 microM, induced a decrease in [Ca(2+)](i) in phagocytes suspended in Ca(2+)-free medium. Lindane needed extracellular calcium to rise [Ca(2+)](i) in phagocytes but not in PBLs. Lindane effects on endoplasmic reticulum (ER) calcium store was examined. In spite of mobilisation by lindane of ER calcium store in phagocytes, it had an opposite effect in PBLs. The composition of the two cell population can explain the differences in calcium modulation observed. [Ca(2+)](i) is an extremely important signal transduction element in physiology and modulation of [Ca(2+)](i) by lindane can be responsible for modulations of immune cell functions. Moreover, sustained rises in [Ca(2+)](i) as observed in our study may be associated with cell death and explained partially the cytotoxicity of this organochlorine insecticide on fish immune cells.
Betoulle
S
S
Laboratory of General and Comparative Immunophysiology, UER of Sciences, 123 av. Albert Thomas, 87060, Limoges, France. sbetoulle@caramail.com
Duchiron
C
C
Deschaux
P
P
D000818:Animals; D002118:Calcium / Q000378:metabolism*; D004721:Endoplasmic Reticulum / Q000187:drug effects / Q000378:metabolism; D001556:Hexachlorocyclohexane / Q000633:toxicity*; D007668:Kidney / Q000276:immunology; D007962:Leukocytes / Q000187:drug effects* / Q000378:metabolism; D017686:Oncorhynchus mykiss; D010586:Phagocytes / Q000187:drug effects* / Q000378:metabolism
D001556:Hexachlorocyclohexane; D002118:Calcium