ArticleThe Journal of general physiology1995
Surface charge and calcium channel saturation in bullfrog sympathetic neurons.
Article in The Journal of general physiology, 1995. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 42 papers.
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Who cites it
42 citing papers in PubMed.
- RBP2 stabilizes slow Cav1.3 CaPflugers Archiv : European journal of physiology · 2020Article
- Single channel measurements demonstrate the voltage dependence of permeation through N-type and L-type CaV channels.Channels (Austin, Tex.) · 2015Article
- Functional expression of α7-nicotinic acetylcholine receptors by muscle afferent neurons.Journal of neurophysiology · 2014Article
- Voltage control of Ca²⁺ permeation through N-type calcium (Ca(V)2.2) channels.The Journal of general physiology · 2014Article
- Proton-sensitive cation channels and ion exchangers in ischemic brain injury: new therapeutic targets for stroke?Progress in neurobiology · 2014Review
- Identification of specific sensory neuron populations for study of expressed ion channels.Journal of visualized experiments : JoVE · 2013Article
- Acid-sensing ion channels in pathological conditions.Advances in experimental medicine and biology · 2013Review
- Fe²⁺ block and permeation of CaV3.1 (α1G) T-type calcium channels: candidate mechanism for non-transferrin-mediated Fe²⁺ influx.Molecular pharmacology · 2012Article
- Domain III regulates N-type (CaV2.2) calcium channel closing kinetics.Journal of neurophysiology · 2012Article
- The role of ASICS in cerebral ischemia.Wiley interdisciplinary reviews. Membrane transport and signaling · 2012Article
- Two sets of amino acids of the domain I of Cav2.3 Ca(2+) channels contribute to their high sensitivity to extracellular protons.Pflugers Archiv : European journal of physiology · 2011Article
- Modulation of acid-sensing ion channels: molecular mechanisms and therapeutic potential.International journal of physiology, pathophysiology and pharmacology · 2011Article
- (R)-roscovitine prolongs the mean open time of unitary N-type calcium channel currents.Neuroscience · 2010Article
- Modulation of the cold-activated cation channel TRPM8 by surface charge screening.The Journal of physiology · 2010Article
- Pharmacological modulation of transmitter release by inhibition of pressure-dependent potassium currents in vestibular hair cells.Naunyn-Schmiedeberg's archives of pharmacology · 2009Article
- Open-state occupancy prevents gating charge relaxation of N-type (CaV2.2) calcium channels.Biophysical journal · 2009Article
- Potassium currents induced by hydrostatic pressure modulate membrane potential and transmitter release in vestibular type II hair cells.Pflugers Archiv : European journal of physiology · 2009Article
- Mechanisms underlying low [Ca(2+)](o)-induced increased excitability of hippocampal neurons.Neuroscience bulletin · 2008Article
- Molecular identity and functional properties of a novel T-type Ca2+ channel cloned from the sensory epithelia of the mouse inner ear.Journal of neurophysiology · 2008Article
- Effects of strontium on the permeation and gating phenotype of calcium channels in hair cells.Journal of neurophysiology · 2008Article
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2 authors.
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Abstract
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 activation could be described by Gouy-Chapman theory, with a surface charge density of 1 e-/140 A2, calculated from the Grahame equation. Changes in ionic strength (replacing N-methyl-D-glucamine with sucrose) shifted the activation curve as expected for a surface charge density of 1 e-/85 A2, in reasonable agreement with the value from changing [Ba2+]o. The instantaneous I-V for fully activated channels also changed with ionic strength, which could be described either by a low surface charge density (less than 1 e-/1,500 A2), or by block by NMG with Kd approximately 300 mM (assuming no surface charge). We conclude that the channel permeation mechanism sees much less surface charge than the gating mechanism. The peak inward current saturated with an apparent Kd = 11.6 mM for Ba2+, while the instantaneous I-V saturated with an apparent Kd = 23.5 mM at 0 mV. This discrepancy can be explained by a lower surface charge near the pore, compared to the voltage sensor. After correction for a surface charge near the pore of 1 e-/1,500 A2, the instantaneous I-V saturated as a function of local [Ba2+]o, with Kd = 65 mM. These results suggest that the channel pore does bind Ba2+ in a saturable manner, but the current-[Ba2+]o relationship may be significantly affected by surface charge.
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