The Subcellular Distribution of Calcium in the Visual Cells of Crayfish Observed with the Combined Oxalate-Pyroantimonate Technique, Depends on Extracellular Calcium

Abstract

1. With the combined oxalate-pyroantimonate method we determined the subcellular distribution of calcium in the photoreceptor cells of the crayfish Orconectes limosus. 2. The calcium antimonate deposits were identified with the electron microscope. Energy-dispersion X-ray analysis verified that the electron dense deposits contained calcium and antimony. 3. Calcium antimonate deposits were found in the submicrovillar cisternae, mitochondria, multivesicular bodies, and pigment granules, as well as in the cytoplasm. 4. The calcium deposits in the cytoplasm of the retinula cell and in the pigment granules were reduced after incubation of the retinae in a solution with a lowered calcium concentration and even more after we permeabilized the plasma membrane with the saponin β-escin. 5. We suppose that the calcium-storing pigment granules participate in the regulation of the cytosolic calcium concentration of the crayfish photoreceptor cells. © 1995, Walter de Gruyter. All rights reserved.