Ephedrine: effects on neuromuscular transmission

Jörn P. Sieb; Andrew G. Engel

doi:10.1016/0006-8993(93)90025-I

Ephedrine: effects on neuromuscular transmission

Jörn P. Sieb, Andrew G. Engel

Neurology

Research output: Contribution to journal › Article › peer-review

41 Scopus citations

Abstract

(-)-Ephedrine has been used in the treatment of patients with myasthenia gravis. To investigate the possible effects of ephedrine on neuromuscular transmission, canine intercostal muscle endplates were studied by microelectrode techniques. At concentrations less than 10^-4 M, ephedrine had no effect on neuromuscular transmission. At a concentration of 10^-4 M, ephedrine increased the quantal content of the endplate potential by 21%. The presynaptic store of acetylcholine quanta available for immediate release was unchanged, but the probability of quantal release was increased by 16%. At this concentration, ephedrine decreased the amplitude of the miniature endplate potential by 38%. In the presence of 10^-3 M ephedrine, the miniature endplate potentials and currents became undetectable. The kinetic properties of the acetylcholine receptor channel were studied by analysis of acetylcholine-induced endplate current noise. At 10^-4 M, ephedrine reduced the channel conductance by 43% but had no effect on the open time. At 5×10^-4 M, ephedrine reduced the channel conductance by 84% and increased the open time by 23 percent.

Original language	English (US)
Pages (from-to)	167-171
Number of pages	5
Journal	Brain Research
Volume	623
Issue number	1
DOIs	https://doi.org/10.1016/0006-8993(93)90025-I
State	Published - Sep 24 1993

Keywords

Catecholamine
Congenital myasthenic syndrome
Myasthenia gravis
Neuromuscular junction
Noise analysis
Transmitter release

ASJC Scopus subject areas

General Neuroscience
Molecular Biology
Clinical Neurology
Developmental Biology

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10.1016/0006-8993(93)90025-I

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title = "Ephedrine: effects on neuromuscular transmission",

abstract = "(-)-Ephedrine has been used in the treatment of patients with myasthenia gravis. To investigate the possible effects of ephedrine on neuromuscular transmission, canine intercostal muscle endplates were studied by microelectrode techniques. At concentrations less than 10-4 M, ephedrine had no effect on neuromuscular transmission. At a concentration of 10-4 M, ephedrine increased the quantal content of the endplate potential by 21%. The presynaptic store of acetylcholine quanta available for immediate release was unchanged, but the probability of quantal release was increased by 16%. At this concentration, ephedrine decreased the amplitude of the miniature endplate potential by 38%. In the presence of 10-3 M ephedrine, the miniature endplate potentials and currents became undetectable. The kinetic properties of the acetylcholine receptor channel were studied by analysis of acetylcholine-induced endplate current noise. At 10-4 M, ephedrine reduced the channel conductance by 43% but had no effect on the open time. At 5×10-4 M, ephedrine reduced the channel conductance by 84% and increased the open time by 23 percent.",

keywords = "Catecholamine, Congenital myasthenic syndrome, Myasthenia gravis, Neuromuscular junction, Noise analysis, Transmitter release",

author = "Sieb, {J{\"o}rn P.} and Engel, {Andrew G.}",

note = "Funding Information: Acknowledgements. Supported by NIH Grant NS 6277 and a research grant from the Muscular Dystrophy Association. Dr. Sieb was the recipient of a postdoctoral fellowship from the 'Deutsche Forschungsgemeinschaft', Germany.",

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N2 - (-)-Ephedrine has been used in the treatment of patients with myasthenia gravis. To investigate the possible effects of ephedrine on neuromuscular transmission, canine intercostal muscle endplates were studied by microelectrode techniques. At concentrations less than 10-4 M, ephedrine had no effect on neuromuscular transmission. At a concentration of 10-4 M, ephedrine increased the quantal content of the endplate potential by 21%. The presynaptic store of acetylcholine quanta available for immediate release was unchanged, but the probability of quantal release was increased by 16%. At this concentration, ephedrine decreased the amplitude of the miniature endplate potential by 38%. In the presence of 10-3 M ephedrine, the miniature endplate potentials and currents became undetectable. The kinetic properties of the acetylcholine receptor channel were studied by analysis of acetylcholine-induced endplate current noise. At 10-4 M, ephedrine reduced the channel conductance by 43% but had no effect on the open time. At 5×10-4 M, ephedrine reduced the channel conductance by 84% and increased the open time by 23 percent.

AB - (-)-Ephedrine has been used in the treatment of patients with myasthenia gravis. To investigate the possible effects of ephedrine on neuromuscular transmission, canine intercostal muscle endplates were studied by microelectrode techniques. At concentrations less than 10-4 M, ephedrine had no effect on neuromuscular transmission. At a concentration of 10-4 M, ephedrine increased the quantal content of the endplate potential by 21%. The presynaptic store of acetylcholine quanta available for immediate release was unchanged, but the probability of quantal release was increased by 16%. At this concentration, ephedrine decreased the amplitude of the miniature endplate potential by 38%. In the presence of 10-3 M ephedrine, the miniature endplate potentials and currents became undetectable. The kinetic properties of the acetylcholine receptor channel were studied by analysis of acetylcholine-induced endplate current noise. At 10-4 M, ephedrine reduced the channel conductance by 43% but had no effect on the open time. At 5×10-4 M, ephedrine reduced the channel conductance by 84% and increased the open time by 23 percent.

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KW - Noise analysis

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Ephedrine: effects on neuromuscular transmission

Abstract

Keywords

ASJC Scopus subject areas

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