the ca2+ ionophore and mersalyl blocked ca2+ uptake , electron microscopy showed electron-dense precipitates in the rough endoplasmic reticulum of saponin-treated cells in the presence of ca2+ , oxalate and atp , which were absent in intact cells and in saponin-cells without atp or pretreated with a23187 .
C0230779
rough endoplasmic reticulum
C0007634
cells