The influence of sodium, potassium and calcium on spontaneous miniature potentials in frog sympathetic ganglion neurons

McIsaac, Robert J.

doi:10.1016/0028-3908(71)90032-3

Cited by 4 publications

(1 citation statement)

References 14 publications

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“…However, quantitation of this difference was difficult because in many control cells most of the m.e.p.s.cs were too small to analyse accurately the decay time course. In addition, even in the presence of an elevated potassium concentration their frequency was very variable (McIsaac, 1971). Further, it was much more difficult to voltage-clamp the control cells (in high K+) for the time required to collect m.e.p.s.cs than those cells maintained in the high potassium solution containing barium.…”

Section: Resultsmentioning

confidence: 99%

Alteration of the fast excitatory postsynaptic current by barium in voltage‐clamped amphibian sympathetic ganglion cells

Connor

Parsons

1984

British J Pharmacology

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Barium‐induced alterations in fast excitatory postsynaptic currents (e.p.s.cs) have been studied in voltage‐clamped bullfrog sympathetic ganglion B cells. In the presence of 2–8 mm barium, e.p.s.c. decay was prolonged and in many cells the e.p.s.c. decay phase deviated from a single exponential function. The decay phase in these cases was more accurately described as the sum of two exponential functions. The frequency of occurrence of a complex decay increased both with increasing barium concentration and with hyperpolarization. Miniature e.p.s.c. decay also was prolonged in barium‐treated cells. E.p.s.c. amplitude was not markedly affected by barium (2–8 mm) in cells voltage‐clamped to — 50 mV whereas at — 90 mV there was a progressive increase in peak size with increasing barium concentration. In control cells the e.p.s.c.‐voltage relationship was linear between −20 and −100 mV; however, this relationship became progressively non‐linear with membrane hyperpolarization in barium‐treated cells. The e.p.s.c. reversal potential was shifted to a more negative value in the presence of barium. There was a voltage‐dependent increase in charge movement during the e.p.s.c. in barium‐treated cells which was not present in control cells. We conclude that the voltage‐dependent alteration in e.p.s.c. decay time course, peak amplitude and charge movement in barium‐treated cells is due to a direct postsynaptic action of barium on the kinetics of receptor‐channel gating in postganglionic sympathetic neurones.

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Section: Resultsmentioning

confidence: 99%

Alteration of the fast excitatory postsynaptic current by barium in voltage‐clamped amphibian sympathetic ganglion cells

Connor

Parsons

1984

British J Pharmacology

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Physiology of the Autonomic Nervous System

Ginsborg¹

1976

Frog Neurobiology

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Dual effect of external calcium on the frequency of miniature synaptic potentials in frog sympathetic ganglion cells

Beume

Pott

1978

Pflugers Arch.

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The effect of calcium on spontaneous transmitter release and on the release induced by tetanic stimulation and by raising the external potassium concentration ([K]0) was studied in sympathetic ganglion cells of Rana esculenta. 1. In standard Ringer's solution the frequency of miniature excitatory postsynaptic potentials (mepsp) ranged from 0.05--2.0 s-1 (0.05 +/- 0.09 s-1, n = 37) at room temperature. 2. At a [K]0 of 2.5 mM mepsp frequency was approximately linearly related to the logarithm of the external calcium concentration (log [Ca]0) (0.1 mM less than or equal to [Ca]0 less than or equal to 20 mM). 3. Duration and amplitude of the potentiation of transmitter release after tetanic preganglionic stimulation increased depending on [Ca]0. 4. Mepsp frequency was strongly dependent on [K]0 between 10 and 20 mM; the frequency being increased to about 40 times control level at a [K]0 of 20 mM. 5. Raising [Ca]0 up to 1.8 mM in high K solutions resulted in an increase in mepsp frequency followed by a decrease at higher [Ca]0. 6. These results are consistent with the idea that the effect of calcium on mepsp frequency depends on: (a) the driving force for calcium entry, (b) the effect of Ca ions on the potential gradient within the nerve membrane.

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The influence of sodium, potassium and calcium on spontaneous miniature potentials in frog sympathetic ganglion neurons

Cited by 4 publications

References 14 publications

Alteration of the fast excitatory postsynaptic current by barium in voltage‐clamped amphibian sympathetic ganglion cells

Alteration of the fast excitatory postsynaptic current by barium in voltage‐clamped amphibian sympathetic ganglion cells

Physiology of the Autonomic Nervous System

Dual effect of external calcium on the frequency of miniature synaptic potentials in frog sympathetic ganglion cells

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