نتایج جستجو برای: sr2 and ba2 cations

تعداد نتایج: 16829594  

Journal: :Crystal Growth & Design 2021

The present work investigates the crystallization and phase evolution of amorphous calcium phosphate (ACP) partially substituted with smaller (Mg2+, Zn2+) larger (Sr2+, Ba2+) divalent ions in range from 1 to 10 mol % (M/P = 1.5:1). It has been demonstrated that ACP tricalcium (TCP) subsequent transformations between TCP polymorphs strongly depend on nature concentration substituents matrix. Two...

Journal: :The Journal of General Physiology 1989
S Grissmer M D Cahalan

Using the patch-clamp whole-cell recording technique, we investigated the influence of external Ca2+, Ba2+, K+, Rb+, and internal Ca2+ on the rate of K+ channel inactivation in the human T lymphocyte-derived cell line, Jurkat E6-1. Raising external Ca2+ or Ba2+, or reducing external K+, accelerated the rate of the K+ current decay during a depolarizing voltage pulse. External Ba2+ also produced...

Journal: :The Journal of General Physiology 2005
Xu-Hui Zeng Xiao-Ming Xia Christopher J. Lingle

Mutational analyses have suggested that BK channels are regulated by three distinct divalent cation-dependent regulatory mechanisms arising from the cytosolic COOH terminus of the pore-forming alpha subunit. Two mechanisms account for physiological regulation of BK channels by microM Ca2+. The third may mediate physiological regulation by mM Mg2+. Mutation of five aspartate residues (5D5N) with...

Journal: :Biophysical journal 2016
Fredrik Elinder Michael Madeja Hugo Zeberg Peter Århem

The transmembrane voltage needed to open different voltage-gated K (Kv) channels differs by up to 50 mV from each other. In this study we test the hypothesis that the channels' voltage dependences to a large extent are set by charged amino-acid residues of the extracellular linkers of the Kv channels, which electrostatically affect the charged amino-acid residues of the voltage sensor S4. Extra...

Journal: :The Journal of neuroscience : the official journal of the Society for Neuroscience 2003
Zu-Cheng Ye Megan S Wyeth Selva Baltan-Tekkok Bruce R Ransom

Little is known about the expression and possible functions of unopposed gap junction hemichannels in the brain. Emerging evidence suggests that gap junction hemichannels can act as stand-alone functional channels in astrocytes. With immunocytochemistry, dye uptake, and HPLC measurements, we show that astrocytes in vitro express functional hemichannels that can mediate robust efflux of glutamat...

Journal: :BMC Pharmacology 2009
James T McLaughlin Sean C Barron Jennifer A See Robert L Rosenberg

Allosteric modulation of membrane receptors is a widespread mechanism by which endogenous and exogenous agents regulate receptor function. For example, several members of the nicotinic receptor family are modulated by physiological concentrations of extracellular calcium ions. In this paper, we examined conformational changes underlying this modulation and compare these with changes evoked by A...

Journal: :The Journal of biological chemistry 1974
H Kimura F Murad

We observed the nonenzymatic formation of guanosine 3’:5’-monophosphate (cyclic GMP) from GTP. The reaction was dependent upon heat and was accelerated by divalent cations and creatine phosphate. The formation of cyclic GMP was greater with increased incubation time, temperature, GTP concentration, and pH. All of the divalent cations tested (Mg2+, Mnz+, Ca2+, Ba2+, and Znzf) increased cyclic GM...

Journal: :The Journal of General Physiology 2003
Ana Y. Estevez Randolph K. Roberts Kevin Strange

The nematode Caenorhabditis elegans offers significant experimental advantages for defining the genetic basis of diverse biological processes. Genetic and physiological analyses have demonstrated that inositol-1,4,5-trisphosphate (IP3)-dependent Ca2+ oscillations in intestinal epithelial cells play a central role in regulating the nematode defecation cycle, an ultradian rhythm with a periodicit...

Journal: :Biochimica et biophysica acta 1990
J W Francis J E Smolen K J Balazovich R R Sandborg L A Boxer

A cell-free assay monitoring lipid mixing was used to investigate the role of Ca2+ in neutrophil membrane-liposome fusion. Micromolar concentrations of Ca2+ were found to directly stimulate fusion of inside-out neutrophil plasma membrane enriched fractions (from neutrophils subjected to nitrogen cavitation) with liposomes (phosphatidylethanolamine:phosphatidic acid, 4:1 molar ratio). In contras...

Journal: :The Biochemical journal 1999
M Estacion W G Sinkins W P Schilling

Trp-like protein (TrpL, where Trp is transient receptor-potential protein) of Drosophila, a non-selective cation channel activated in photoreceptor cells by a phospholipase C-dependent mechanism, is thought to be a prototypical receptor-activated channel. Our previous studies showed that TrpL channels are not activated by depletion of internal Ca2+ stores when expressed in Sf9 cells. Using fura...

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