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The role of calcium on protein secretion of the albumen gland in Helisoma duryi (Gastropoda)
Author(s) -
Kiehn Lana,
Mukai Spencer T.,
Saleuddin A. Saber M.
Publication year - 2004
Publication title -
invertebrate biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.486
H-Index - 42
eISSN - 1744-7410
pISSN - 1077-8306
DOI - 10.1111/j.1744-7410.2004.tb00164.x
Subject(s) - secretion , biology , endoplasmic reticulum , medicine , endocrinology , ryanodine receptor , phospholipase c , inositol trisphosphate , receptor , inositol , microbiology and biotechnology , signal transduction , biochemistry
. The albumen gland of the freshwater pulmonate snail Helisoma duryi produces and secretes the perivitelline fluid, which coats fertilized eggs and provides nutrients to the developing embryos. It is known that perivitelline fluid secretion is stimulated by dopamine through the activation of a dopamine D 1 ‐like receptor, which in turn stimulates cAMP production leading to the secretion of perivitelline fluid. This paper examines the glandular release of perivitelline fluid and provides evidence for the role of Ca 2+ in the regulated secretion of perivitelline fluid based on protein secretion experiments and inositol 1,4,5‐trisphosphate assays. Dopamine‐stimulated protein secretion by the albumen gland is reduced in Ca 2+ ‐free medium or in the presence of plasma membrane Ca 2+ channel blockers, although the Ca 2+ channel subtype involved is unclear. In addition, dopamine‐stimulated protein secretion does not directly involve phospholipase C‐generated signaling pathways and Ca 2+ release from intracellular stores. Sarcoplasmic/endoplasmic reticulum Ca 2+ ‐ATPase inhibitors had little effect on protein secretion when applied alone; however, they potentiated dopamine‐stimulated protein secretion. Dantrolene, an inhibitor of ryanodine receptors, 8‐(N,N‐diethylamino)‐octyl‐3,4,5‐trimethoxybenzoate hydrochloride, a nonspecific inhibitor of intracellular Ca 2+ channels, and 2‐aminoethyldiphenylborate, an inhibitor of inositol 1,4,5‐trisphosphate receptors, did not suppress protein secretion, suggesting Ca 2+ release from internal stores does not directly regulate protein secretion. Thus, the influx of Ca 2+ from the extracellular space appears to be the major pathway mediating protein secretion by the albumen gland. The results are discussed with respect to the role of Ca 2+ in controlling exocytosis of proteins from the albumen gland secretory cells.