Key result
Lowering the pipette Ba2+ concentration to 20 mM dramatically increased the frequency of L-type Ca2+ channel repolarization openings in hippocampal neurons compared to 110 mM Ba2+.
Population
193 patches from primary cultures of fetal rat hippocampus (pregnant Fischer 344 rats)
Comparison
Low Ba2+ or low Ca2+ in the recording pipette vs High Ba2+ (110 mM) in the recording pipette
Design
Preclinical
Authors
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Hypothesis-generating for L-type channel gating in neurons; leaves open relevance to human cardiac Ca2+ signaling.
Absolute Event Rate: 77% vs 34%
Lowering extracellular divalent cation concentrations dramatically increases the probability of sustained repolarization openings of L-type Ca2+ channels in hippocampal neurons, which may underlie long-lasting Ca2+-dependent physiological processes.
Thibault et al. (1993) studied Normal physiology (n=193). Low Ba2+ concentration vs. 110 mM Ba2+ was evaluated on Proportion of patches exhibiting at least one clear repolarization opening (RO) from a holding potential of -70 mV. Lowering the pipette Ba2+ concentration to 20 mM dramatically increased the frequency of L-type Ca2+ channel repolarization openings in hippocampal neurons compared to 110 mM Ba2+.
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