The mechanism ofthe Bat+-induced contraction was investigated using intact and saponin-treated skinned smooth muscle (skinned muscle) strips of the rabbit mesenteric artery . After depletion of Ca21 stored in the caffeinesensitive site, >0 .65 mM Ba2+ evoked contraction in muscle strips depolarized with 128 mM K+ in Cat+-free solution in a dose-dependent fashion, and the ED50 values for Ca2' an...

The effects of Ca2+, Sr2+, and Ba2+ on spontaneous and evoked glycinergic inhibitory postsynaptic currents (mIPSCs and eIPSCs) were studied using the "synaptic bouton" preparation of rat spinal neurons and conventional whole cell recording under voltage-clamp conditions. In response to application of Ca2+-free solution, the frequency of mIPSC initially rapidly decreased to 40 approximately 50% ...

To clarify the energy-expenditure mechanism during Ba2+ contracture of mechanically unloaded rat left ventricular (LV) slices, we measured myocardial O2 consumption (V˙o 2) of quiescent slices in Ca2+-free Tyrode solution andV˙o 2 during Ba2+ contracture by substituting Ca2+ with Ba2+. We then investigated the effects of cyclopiazonic acid (CPA) and 2,3-butanedione monoxime (BDM) on the Ba2+ co...

Currents carried by Ba2+ through calcium channels were recorded in the whole-cell configuration in isolated frog sympathetic neurons. The effect of surface charge on the apparent saturation of the channel with Ba2+ was examined by varying [Ba2+]o and ionic strength. The current increased with [Ba2+]o, and the I-V relation and the activation curve shifted to more positive voltages. The shift of ...

We report extended x-ray absorption fine-structure EXAFS studies of nand p-type Ba8Ga16Ge30 samples type-I clathrate at the Ga, Ge, and Ba K edges, to probe the local structure, particularly around the Ba atoms located inside 20and 24-atom cages Ba1 and Ba2 sites, respectively composed of Ga/Ge atoms. In agreement with diffraction analysis, we find Ba2 is off center, with a component in the bc ...

The interaction of Ca2+ and Ba2+ with a Ca2+-activated K+ channel from rabbit skeletal muscle membranes is studied in planar lipid bilayers. At [Ca2+] greater than or equal to 100 microM in the cis side (the side to which the vesicles are added) and at positive voltages, the channel kinetics consisted of bursts of activity interrupted by long periods of quiescence. We found that the reciprocal ...

A Gram-stain-negative, aerobic, non-spore-forming, non-flagellated and coccoid, ovoid or rod-shaped bacterial strain, W-BA2(T), was isolated from a brown algae reservoir in Wando of South Korea. Strain W-BA2(T) grew optimally at 25 °C, at pH 7.0-8.0 and in the presence of approximately 2.0-3.0% (w/v) NaCl. Phylogenetic trees based on 16S rRNA gene sequences revealed that strain W-BA2(T) fell wi...

Single high-conductance Ca2+-activated K+ channels from rat skeletal muscle were inserted into planar lipid bilayers, and discrete blocking by the Ba2+ ion was studied. Specifically, the ability of external K+ to reduce the Ba2+ dissociation rate was investigated. In the presence of 150 mM internal K+, 1-5 microM internal Ba2+, and 150 mM external Na+, Ba2+ dissociation is rapid (5 s-1) in exte...

This paper presents electrophysiological evidence that small changes in [K+]o modulate the activity of the Na+-K+ pump on the apical membrane of the frog retinal pigment epithelium (RPE). This membrane also has a large relative K+ conductance so that lowering [K+]o hyperpolarizes it and therefore increases the transepithelial potential (TEP). Ba2+, a K+ channel blocker, eliminated these normal ...

Ionic mechanisms underlying Ba2+-induced automaticity in the bullfrog atrial muscle were studied by performing current and voltage clamp experiments using the double sucrose-gap technique. The application of Ba2+ of more than 0.01 mM induced membrane depolarization, and its amplitude became larger with increasing [Ba2+]o. Pacemaker activity was initiated above 0.3 mM Ba2+. Voltage clamp experim...