M. Sandbacka et al., Rainbow trout gill epithelial cells in primary culture communicate throughgap junctions as demonstrated by dye-coupling, FISH PHYS B, 19(3), 1998, pp. 287-292
Communication across gap junctions between cells in various tissues is cons
idered an important mechanism for control of cellular growth, differentiati
on and function. Although cell-cell coupling in the gill epithelium is like
ly for functional reasons, the common view is that gap junctions are not pr
esent between cells in the gill epithelium of teleostean fish. Gap junction
mediated cell-cell communication was analysed in the present study in prim
ary and secondary cultures of rainbow trout gill epithelial cells by microi
njecting the fluorescent dye Lucifer yellow CH. In 4-14 day old primary and
secondary cell cultures, 58% of the cells injected with Lucifer yellow wer
e coupled to at least one other cell. To exclude the possibility that inter
cellular dye transfer occurred through cytoplasmic bridges instead of gap j
unctions, we also microinjected FITC-dextran, which because of its molecula
r size does not pass through gap junctions. None of the cells injected with
FITC-dextran showed spreading of the dye. The number of cells spreading Lu
cifer yellow was decreased in a dose-dependent way when the cells were trea
ted with dioctanoylglycerol, a synthetic diacylglycerol known to affect the
open state of gap junctions, which further supports that the cells are cou
pled through functional gap junctions.