The recently synthesized calcium indicator quin -2 was incorporated into synaptosomes from guinea-pig cerebral cortex following uptake and internal hydrolysis of quin -2 tetra-acetoxymethyl ester. Incubation in physiological media containing 1 mM- or 2 mM-CaCl2 led to equilibrium cytosolic ionized calcium concentrations of 85 +/- 10 nM and 205 +/- 5 nM respectively (mean +/- S.E.M. from eight a...

PURPOSE To investigate in bovine and embryonic chicken lens cultures the effects of elevated intracellular calcium on the permeability of gap junctions. To determine the changes in intracellular calcium using fura-2. To detect any changes in the phosphorylation of connexin43 after ionophore treatment. METHODS Lucifer yellow was micro-injected into individual cells, and dye spread to neighbori...

Damage to skeletal muscles may be mediated via free radicals or intracellular calcium overload. To look for inter-relationships between these pathways we have examined the effect of intracellular Ca overload on muscles from rats fed on either a vitamin E-deficient or vitamin E-sufficient diet and assessed the non-enzymic lipid peroxidation in these muscles by examining the production of thiobar...

Low concentrations of calcium and magnesium ions have been shown to influence microtubule assembly in vitro. To test whether these cations also have an effect on microtubules in vivo, specimens of Actinosphaerium eichhorni were exposed to different concentrations of Ca++ and Mg++ and the divalent cation ionophore A23187. Experimental degradation and reformation of axopodia were studied by light...

BACKGROUND Before a spermatozoon can fertilize an oocyte it must undergo a cascade of biochemical and physiological changes that facilitate its binding and penetration into the oocyte. Epididymal protease inhibitor (eppin) has been found to play a critical role in male fertility through an immunological approach. METHODS In this study, we used an anti-eppin antibody to clarify the effect of e...

Calcium ions (Ca(2+)) are indispensable for the physiology of organisms and the molecular regulation of cells. We observed that CGK733, a synthetic chemical substance, induced non-apoptotic cell death and stimulated reversible calcium sequestration by vesicles in pancreatic cancer cells. The endoplasmic reticulum (ER) stress eukaryotic translation initiation factor 2-alpha kinase 3/C/EBP homolo...

Intestinal mitochondria have a phospholipase D (PLD) activity which was stimulated by polyamines and monoamines resulting in the formation of phosphatidic acid (PA) from endogenous phospholipids. When stimulated by polyamines, mitochondrial PLD utilized endogenous phosphatidylethanolamine (PE) as substrate whereas stimulated by monoamines, both PE and phosphatidylcholine (PC) were hydrolysed. S...

Incubation of the bovine endothelial cell line, CPAE, with leukotriene D4, leukotriene C4, bradykinin, or the calcium ionophore A23187 results in the release of arachidonic acid metabolites including 6-keto-prostaglandin F1 alpha, the stable metabolite of prostacyclin. Pretreatment of these cells with the pertussis toxin islet-activating protein (IAP) results in a dose-dependent inhibition of t...