A regional experiment was conducted to test the hypothesis that the concentration of dietary Ca does not affect the digestibility of Ca or P in diets fed to growing pigs. Six diets based on corn, potato protein isolate, cornstarch, and soybean oil were formulated. All diets also contained monosodium phosphate, crystalline AA, salt, and a vitamin-micromineral premix. The only difference among th...

We determined the Ca(2+) dependence and time course of the modulation of ligand sensitivity in cGMP-gated currents of intact cone photoreceptors. In electro-permeabilized single cones isolated from striped bass, we measured outer segment current amplitude as a function of cGMP or 8Br-cGMP concentrations in the presence of various Ca(2+) levels. The dependence of current amplitude on nucleotide ...

Human cerebral cortical synaptosomes were used to study voltage-dependent Ca(2+) channels mediating calcium influx in human axon terminals. Synaptosomes were depolarized by elevation of the extracellular K(+) concentration by 30 mM or by the addition of veratridine (10 microM). Increase in cytosolic concentration of calcium [Ca(2+)](i) induced by either stimulus was abolished in the absence of ...

The role of calcium ions (Ca) in the generation of transient depolarizations (TDs) by acetylstrophanthidin was examined. Transmembrane activity was recorded from isolated canine false tendons exposed to acetylstrophanthidin; concentrations from 7.5 X 10"" to 2 X 10-" g/ml caused TDs coupled to driven action potentials and depressed slow diastolic depolarization. TDs could reach threshold and in...

The role of calcium ions (Ca) in the generation of transient depolarizations (TDs) by acetylstrophanthidin was examined. Transmembrane activity was recorded from isolated canine false tendons exposed to acetylstrophanthidin; concentrations from 7.5 X 10"" to 2 X 10-" g/ml caused TDs coupled to driven action potentials and depressed slow diastolic depolarization. TDs could reach threshold and in...

The influence of humic substances (HS) and calcium (Ca) on cadmium (Cd) toxicity was determined using zebrafish (Danio rerio). Embryo and larvae of the zebrafish were exposed to various Cd concentrations (1.8; 2.8; 4.2; 6.2; 9.3 mg/l Cd) for 144 h. Combinations of low (0.2 mmol/l) and high (2 mmol/l) Ca, +HS (5 mg/l C) or -HS were used during Cd exposure. The toxicity of Cd was affected by (1) ...

Antagonists of myosin light chain (MLC) kinase (MLCK) and Rho kinase (ROK) are thought to inhibit hypoxic pulmonary vasoconstriction (HPV) by decreasing the concentration of phosphorylated MLC at any intracellular Ca(2+) concentration ([Ca(2+)](i)) in pulmonary arterial smooth muscle cells (PASMC); however, these antagonists can also decrease [Ca(2+)](i). To determine whether MLCK and ROK antag...

des monocristaux de fluoraptite calcique dopes avec des ions mn substitues aux ions ca ont ete prepares en utilisant une methode de synthese qui permet de l'obtenir avec une faible concentration en defauts le long de l'axe senaire helicoidal. dans ces conditions les spectres d'excitation et de rpe montrent que les ions mn se placent uniquement dans ie site ca(l).