Ca2+ uptake to purified secretory vesicles from bovine neurohypophyses

Calcium/sodium exchange in purified secretory vesicles from bovine neurohypophyses

“…The apparent concentration of Na+ (24 mM) within the secretory vesicles analyzed is higher than that in the cytoplasm (7). The concentration of free cytoplasmic Ca 2 + in several systems varies between 0.1-10 ~M (26).…”

“…2). On the other hand, Na+/Ca 2 + exchange is not affected by Mg 2 +, neither in secretory vesicles from the neurohypophysis, nor from adrenal medulla (7,33). These facts allowed to measure selectively Na+ dependent Ca 2 + uptake (in the presence of Mg 2 +).…”

“…(glutamate dehydrogenase) . It has been described earlier that secretory vesicles accumulate Ca 2 + even in presence of ruthenium red and that this process is not stimulated by ATP (7). By contrast Ca 2 + uptake into neurohvpophysial mitochondria1 fractions was stimu1ated by ATP (7).…”

“…The hormone-containing neurohypophyseal secretory vesicles within the terminals also contain Ca 2 +, as shown both by electron probe analysis of intact tissue (6) as weIl as by analyses of vesicles isolated by subcellular fractionation (7,8).…”

Distribution of chromaffin secretory vesicles, acetylcholinesterase, and lysosomal enzymes in sucrose and percoll gradients

“…The main contaminants of cmde secretory vesicle fractions (Le., those obtained by differential centrifugation) are mitochondria, which can be completely removed using such gradients. The vesicles obtained are stable and have successfully been used in studies concerned with the analysis of proton, sotium, and calcium transport (6,7,13,20,(12)(13)(14)(15)(16)(17)(18)(19)(20)(21)(22)(23)(24).…”