Illumination partly reverses the postsynaptic blockade of the frog neuromuscular junction by the styryl pyridinium dye RH414

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Abstract

The styryl pyridinium dye RH414, which we have used recently for optical monitoring of synaptic vesicle membrane trafficking in frog motor nerve terminals, reversibly inhibited contractions in the frog nerve-muscle preparations used for those studies. We report here the results of experiments into the basis of this inhibition and how the blocking effects can be modulated by incident light, by using conventional intracellular recording and iontophoretic techniques. Bath application of 5-42.5 microM RH414 blocked nerve-evoked twitches in frog cutaneus pectoris muscles, although subthreshold endplate potentials and miniature endplate potentials could still be recorded. In the presence of the dye, illumination of the recording area with light from a mercury arc lamp over a wide range of wavelengths (340-560 nm) potentiated the amplitude of endplate potentials, miniature endplate potentials, and depolarizations resulting from iontophoretic application of acetylcholine. The magnitude of both the light-induced disinhibition of endplate and iontophoretic potentials increased with the intensity of the illumination and developed exponentially with a time constant of several hundred milliseconds. Both the dye-induced inhibition and the light-induced disinhibition disappeared after washing in dye-free physiological saline. Muscle fibre resting membrane potential, input conductance and miniature endplate potential frequency, however, were not affected by these manipulations. These data are consistent with a specific, curare-like interaction of the dye with acetylcholine receptors which can be modulated by light.
Original languageEnglish
Pages (from-to)201-207
Number of pages7
JournalProceedings of the Royal Society of London. B, Biological Sciences
Volume258
Issue number1352
DOIs
Publication statusPublished - 22 Nov 1994

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Neuromuscular Junction
Lighting
frog
Anura
dyes
lighting
frogs
dye
Coloring Agents
Light
Muscle
muscle
nerve tissue
Arc lamps
Curare
membrane
Membranes
Mercury vapor lamps
Synaptic Membranes
Muscles

Keywords

  • Acetylcholine
  • Animals
  • Light
  • Muscle, Skeletal
  • Neuromuscular Blocking Agents
  • Neuromuscular Junction
  • Pyridinium Compounds
  • Rana pipiens

Cite this

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title = "Illumination partly reverses the postsynaptic blockade of the frog neuromuscular junction by the styryl pyridinium dye RH414",
abstract = "The styryl pyridinium dye RH414, which we have used recently for optical monitoring of synaptic vesicle membrane trafficking in frog motor nerve terminals, reversibly inhibited contractions in the frog nerve-muscle preparations used for those studies. We report here the results of experiments into the basis of this inhibition and how the blocking effects can be modulated by incident light, by using conventional intracellular recording and iontophoretic techniques. Bath application of 5-42.5 microM RH414 blocked nerve-evoked twitches in frog cutaneus pectoris muscles, although subthreshold endplate potentials and miniature endplate potentials could still be recorded. In the presence of the dye, illumination of the recording area with light from a mercury arc lamp over a wide range of wavelengths (340-560 nm) potentiated the amplitude of endplate potentials, miniature endplate potentials, and depolarizations resulting from iontophoretic application of acetylcholine. The magnitude of both the light-induced disinhibition of endplate and iontophoretic potentials increased with the intensity of the illumination and developed exponentially with a time constant of several hundred milliseconds. Both the dye-induced inhibition and the light-induced disinhibition disappeared after washing in dye-free physiological saline. Muscle fibre resting membrane potential, input conductance and miniature endplate potential frequency, however, were not affected by these manipulations. These data are consistent with a specific, curare-like interaction of the dye with acetylcholine receptors which can be modulated by light.",
keywords = "Acetylcholine, Animals, Light, Muscle, Skeletal, Neuromuscular Blocking Agents, Neuromuscular Junction, Pyridinium Compounds, Rana pipiens",
author = "Bewick, {Guy Smith} and Betz, {W J}",
year = "1994",
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TY - JOUR

T1 - Illumination partly reverses the postsynaptic blockade of the frog neuromuscular junction by the styryl pyridinium dye RH414

AU - Bewick, Guy Smith

AU - Betz, W J

PY - 1994/11/22

Y1 - 1994/11/22

N2 - The styryl pyridinium dye RH414, which we have used recently for optical monitoring of synaptic vesicle membrane trafficking in frog motor nerve terminals, reversibly inhibited contractions in the frog nerve-muscle preparations used for those studies. We report here the results of experiments into the basis of this inhibition and how the blocking effects can be modulated by incident light, by using conventional intracellular recording and iontophoretic techniques. Bath application of 5-42.5 microM RH414 blocked nerve-evoked twitches in frog cutaneus pectoris muscles, although subthreshold endplate potentials and miniature endplate potentials could still be recorded. In the presence of the dye, illumination of the recording area with light from a mercury arc lamp over a wide range of wavelengths (340-560 nm) potentiated the amplitude of endplate potentials, miniature endplate potentials, and depolarizations resulting from iontophoretic application of acetylcholine. The magnitude of both the light-induced disinhibition of endplate and iontophoretic potentials increased with the intensity of the illumination and developed exponentially with a time constant of several hundred milliseconds. Both the dye-induced inhibition and the light-induced disinhibition disappeared after washing in dye-free physiological saline. Muscle fibre resting membrane potential, input conductance and miniature endplate potential frequency, however, were not affected by these manipulations. These data are consistent with a specific, curare-like interaction of the dye with acetylcholine receptors which can be modulated by light.

AB - The styryl pyridinium dye RH414, which we have used recently for optical monitoring of synaptic vesicle membrane trafficking in frog motor nerve terminals, reversibly inhibited contractions in the frog nerve-muscle preparations used for those studies. We report here the results of experiments into the basis of this inhibition and how the blocking effects can be modulated by incident light, by using conventional intracellular recording and iontophoretic techniques. Bath application of 5-42.5 microM RH414 blocked nerve-evoked twitches in frog cutaneus pectoris muscles, although subthreshold endplate potentials and miniature endplate potentials could still be recorded. In the presence of the dye, illumination of the recording area with light from a mercury arc lamp over a wide range of wavelengths (340-560 nm) potentiated the amplitude of endplate potentials, miniature endplate potentials, and depolarizations resulting from iontophoretic application of acetylcholine. The magnitude of both the light-induced disinhibition of endplate and iontophoretic potentials increased with the intensity of the illumination and developed exponentially with a time constant of several hundred milliseconds. Both the dye-induced inhibition and the light-induced disinhibition disappeared after washing in dye-free physiological saline. Muscle fibre resting membrane potential, input conductance and miniature endplate potential frequency, however, were not affected by these manipulations. These data are consistent with a specific, curare-like interaction of the dye with acetylcholine receptors which can be modulated by light.

KW - Acetylcholine

KW - Animals

KW - Light

KW - Muscle, Skeletal

KW - Neuromuscular Blocking Agents

KW - Neuromuscular Junction

KW - Pyridinium Compounds

KW - Rana pipiens

U2 - 10.1098/rspb.1994.0163

DO - 10.1098/rspb.1994.0163

M3 - Article

VL - 258

SP - 201

EP - 207

JO - Proceedings of the Royal Society of London. B, Biological Sciences

JF - Proceedings of the Royal Society of London. B, Biological Sciences

SN - 0962-8452

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ER -