Voltage-dependent calcium channels (VDCCs) play an essential role in regulating cerebral artery diameter and it is widely appreciated that the L-type VDCC, CaV1.2, encoded by the CACNA1C gene, is a principal Ca2+ entry pathway in vascular myocytes. However, electrophysiological studies using 10 mM extracellular barium ([Ba2+]o) as a charge carrier have shown that ~20% of VDCC currents in cerebr...

Effect of alkaline earth metal ions on induction of the competence for DNA transfection was investigated. Unlike spheroplasts, the bulk of the bacteria treated with these ions retains colony-forming ability. The order of effectiveness for transfection of phiA replicative-form DNA has been found to be Ba2+ greater than Ca2+ greater than Sr2+ greater than Mg2+. The competence of Ba2+-treated cell...

The conduction properties of the alkaline earth divalent cations were determined in the purified sheep cardiac sarcoplasmic reticulum ryanodine receptor channel after reconstitution into planar phospholipid bilayers. Under bi-ionic conditions there was little difference in permeability among Ba2+, Ca2+, Sr2+, and Mg2+. However, there was a significant difference between the divalent cations and...

Planar lipid bilayer recordings were used to study Ca channels from bovine cardiac sarcolemmal membranes. Ca channel activity was recorded in the absence of nucleotides or soluble enzymes, over a range of membrane potentials and ionic conditions that cannot be achieved in intact cells. The dihydropyridine-sensitive L-type Ca channel, studied in the presence of Bay K 8644, was identified by a de...

In this study, high-conductance Ca2+-activated K+ channels from rat skeletal muscle were incorporated into planar phospholipid bilayers, and discrete blockade of single channels by Ba2+ was studied. With 150 mM K+ held constant in the internal solution, increasing external K+ over the range 100-1,000 mM raises the rate of Ba2+ dissociation. This "enhancement effect," which operates at K+ concen...

Ca2+ -dependent inactivation (CDI) has recently been shown in heterologously expressed N-type calcium channels (CaV2.2), but CDI has been inconsistently observed in native N-current. We examined the effect of Ca2+ on N-channel inactivation in rat sympathetic neurons to determine the role of CDI on mammalian N-channels. N-current inactivated with fast (tau approximately 150 ms) and slow (tau app...

Strong inward rectifier potassium channels are expressed by some vascular smooth muscle cells and facilitate K+-induced hyperpolarization. Using whole cell patch clamp of isolated descending vasa recta (DVR), we tested whether strong inward rectifier K+ currents are present in smooth muscle and pericytes. Increasing extracellular K+ from 5 to 50 and 140 mmol/l induced inward rectifying currents...

Image-model coupling: application to an ionospheric storm N.D. Smith1,*, D. Pokhotelov2, C.N. Mitchell2, and C.J. Budd1 1Department of Mathematical Sciences, University of Bath, U.K., BA2 7AY 2Department of Electronic and Electrical Engineering, University of Bath, U.K., BA2 7AY *Completed while with the Department of Electronic and Electrical Engineering, University of Bath Correspondence to: ...

DNA Nanostructures Xing Wang, Arun Richard Chandrasekaran and co-workers assembled nanostructures in a wide variety of ions (Ca2+, Ba2+, Na+, K+ Li+). monovalent (Na+, Li+) exhibit higher nuclease resistance compared to those divalent (Mg2+, Ca2+ Ba2+). In article number 2300040, the authors present new assembly conditions for range with enhanced biostability. Image is an acrylic painting by Ar...

High-voltage activated Ca channels in tiger salamander cone photoreceptors were studied with nystatin-permeabilized patch recordings in 3 mM Ca2+ and 10 mM Ba2+. The majority of Ca channel current was dihydropyridine sensitive, suggesting a preponderance of L-type Ca channels. However, voltage-dependent, incomplete block (maximum 60%) by nifedipine (0.1-100 microM) was evident in recordings of ...