Proceedings of the National Academy of Sciences · 1978 · 183 citations · 20 references
Life SciencesNeurosciencePhysiologyElectrophysiologyNeurophysiologySignal TransductionCalcium SignalingIntracellular Calcium SignalingIon Channel PhysiologyIon Channel RegulationIon PermeationMembrane ElectrophysiologyCalcium Channel FunctionCalcium Channel PhysiologyCalcium Influx MechanismsCalcium Signaling BiophysicsCalcium-induced Calcium ReleaseCompetitive Binding InteractionsElectrophysiological SignalingResponsiveness
Electrical stimulation with radiofrequency fields amplitude-modulated at brain wave frequencies increased 45Ca2+ efflux from isolated chicken cerebral tissue. The response was not sensitive to variations of the calcium concentration (0-4.16 mM) in the bathing solution but was enhanced by addition of H+ (0.108 mM HCl) and inhibited in the absence of normal bicarbonate levels (2.4 mM). Addition of lanthanum to the bicarbonate-free solution restored electrical responsiveness, but the stimulus decreased instead of increasing 45Ca2+ efflux. It is suggested that low-frequency, weak, extracellular electric gradients may be transduced in a specific class of extracellular negative binding sites normally occupied by Ca2+ and susceptible to competitive H+ binding.
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