M. Suzuki et al., ATP-INDUCED INCREASE IN INTRACELLULAR CA2-PIGS( CONCENTRATION IN THE CULTURED MARGINAL CELL OF THE STRIA VASCULARIS OF GUINEA), Hearing research, 86(1-2), 1995, pp. 68-76
The primary culture of marginal cells from the explant of the stria va
scularis of guinea-pigs was established and confirmed by morphological
, immunohistochemical and physiological characters of the cultivated c
ells. The positive stain of cytokeratin 18 without vimentin and desmin
expressions indicated the epithelial origin of the cultured polygonal
cells. Electron microscopical findings of cultured cells resembled th
e morphological characteristics of marginal cells. The addition of 100
mu M ouabain to the cultured cells significantly increased the intrac
ellular Na+ concentration, providing the evidence for the presence of
Na+ pump. Using the cultured marginal cells identified by the above-me
ntioned findings, the effects of neurotransmitters and hormones in reg
ulating intracellular Ca2+ concentration ([Ca2+](i)) were investigated
. The addition of 10(-4) M ATP caused an increase in [Ca2+](i), which
was independent of the presence of extracellular Ca2+. The rank order
of agonist potency was ATP > alpha,beta-methylene ATP > ADP. Adenosine
, however, evoked no response. Cultured marginal cells may possess P-2
-purinergic receptors which mobilize Ca2+ from the intracellular Ca2pool. [Marginal cell, Cell culture, Na+/K(+)ATPase, Intracellular Ca2 concentration, ATP].