A quantitative study of the enhancing effect of nickel ions on the taste response to sodium ions of single fibers of the frog glossopharyngeal nerve

Competitive inhibition by calcium ions of the nickel-enhanced response to sodium ions

Yasuyuki Kitada, Yoshihiro Mitoh

Research output: Contribution to journalArticle

2 Citations (Scopus)

Abstract

Single water fibers of the frog glossopharyngeal nerve respond to relatively high concentrations of NaCl (>80 mM). NiCl2 at 1 mM enhanced the Na+ response and reduced the threshold concentration for NaCl to 20 mM. CaCl2 at 0.5-1 mM induced an inhibition of the Ni2+-enhanced response to Na+ ions. A quantitative explanations for these results is provided by the hypothesis that Ni2+ ions secondarily affect a sodium receptor or channel (designated XNa*) that is responsible for the Na+ response and that Ca2+ ions inhibit the Ni2+-enhanced response to Na+ ions by competing with Na+ ions for XNa*. Double-reciprocal plots of the experimental data indicate that the affinity of XNa* for both Na+ ions (agonist) and Ca2+ ions (competitive antagonist) in the presence of 1 mM NiCl2 was five times higher than the previously reported values obtained in the absence of NiCl2 (Kitada, 1991). Ni2+ ions at 1 mM enhanced the maximal response to Na+ ions by 190%. It appears that a sodium receptor (or channel) interacts with a Ni2+-binding element that is affected by Ni2+ ions and, thus, Ni2+ ions can induce both an increase in the affinity of the sodium receptor for the respective cations and an enhancement of the Na+ response.

Original languageEnglish
Pages (from-to)65-73
Number of pages9
JournalChemical Senses
Volume21
Issue number1
Publication statusPublished - 1996

Fingerprint

Glossopharyngeal Nerve
Nickel
nickel
Anura
frogs
nerve tissue
Sodium
sodium
Ions
ions
Calcium
calcium
receptors
Inhibition (Psychology)
agonists
Cations
antagonists
cations

ASJC Scopus subject areas

  • Agricultural and Biological Sciences (miscellaneous)
  • Food Science
  • Physiology
  • Physiology (medical)
  • Neuroscience(all)
  • Behavioral Neuroscience

Cite this

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title = "A quantitative study of the enhancing effect of nickel ions on the taste response to sodium ions of single fibers of the frog glossopharyngeal nerve: Competitive inhibition by calcium ions of the nickel-enhanced response to sodium ions",
abstract = "Single water fibers of the frog glossopharyngeal nerve respond to relatively high concentrations of NaCl (>80 mM). NiCl2 at 1 mM enhanced the Na+ response and reduced the threshold concentration for NaCl to 20 mM. CaCl2 at 0.5-1 mM induced an inhibition of the Ni2+-enhanced response to Na+ ions. A quantitative explanations for these results is provided by the hypothesis that Ni2+ ions secondarily affect a sodium receptor or channel (designated XNa*) that is responsible for the Na+ response and that Ca2+ ions inhibit the Ni2+-enhanced response to Na+ ions by competing with Na+ ions for XNa*. Double-reciprocal plots of the experimental data indicate that the affinity of XNa* for both Na+ ions (agonist) and Ca2+ ions (competitive antagonist) in the presence of 1 mM NiCl2 was five times higher than the previously reported values obtained in the absence of NiCl2 (Kitada, 1991). Ni2+ ions at 1 mM enhanced the maximal response to Na+ ions by 190{\%}. It appears that a sodium receptor (or channel) interacts with a Ni2+-binding element that is affected by Ni2+ ions and, thus, Ni2+ ions can induce both an increase in the affinity of the sodium receptor for the respective cations and an enhancement of the Na+ response.",
author = "Yasuyuki Kitada and Yoshihiro Mitoh",
year = "1996",
language = "English",
volume = "21",
pages = "65--73",
journal = "Chemical Senses",
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T2 - Competitive inhibition by calcium ions of the nickel-enhanced response to sodium ions

AU - Kitada, Yasuyuki

AU - Mitoh, Yoshihiro

PY - 1996

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N2 - Single water fibers of the frog glossopharyngeal nerve respond to relatively high concentrations of NaCl (>80 mM). NiCl2 at 1 mM enhanced the Na+ response and reduced the threshold concentration for NaCl to 20 mM. CaCl2 at 0.5-1 mM induced an inhibition of the Ni2+-enhanced response to Na+ ions. A quantitative explanations for these results is provided by the hypothesis that Ni2+ ions secondarily affect a sodium receptor or channel (designated XNa*) that is responsible for the Na+ response and that Ca2+ ions inhibit the Ni2+-enhanced response to Na+ ions by competing with Na+ ions for XNa*. Double-reciprocal plots of the experimental data indicate that the affinity of XNa* for both Na+ ions (agonist) and Ca2+ ions (competitive antagonist) in the presence of 1 mM NiCl2 was five times higher than the previously reported values obtained in the absence of NiCl2 (Kitada, 1991). Ni2+ ions at 1 mM enhanced the maximal response to Na+ ions by 190%. It appears that a sodium receptor (or channel) interacts with a Ni2+-binding element that is affected by Ni2+ ions and, thus, Ni2+ ions can induce both an increase in the affinity of the sodium receptor for the respective cations and an enhancement of the Na+ response.

AB - Single water fibers of the frog glossopharyngeal nerve respond to relatively high concentrations of NaCl (>80 mM). NiCl2 at 1 mM enhanced the Na+ response and reduced the threshold concentration for NaCl to 20 mM. CaCl2 at 0.5-1 mM induced an inhibition of the Ni2+-enhanced response to Na+ ions. A quantitative explanations for these results is provided by the hypothesis that Ni2+ ions secondarily affect a sodium receptor or channel (designated XNa*) that is responsible for the Na+ response and that Ca2+ ions inhibit the Ni2+-enhanced response to Na+ ions by competing with Na+ ions for XNa*. Double-reciprocal plots of the experimental data indicate that the affinity of XNa* for both Na+ ions (agonist) and Ca2+ ions (competitive antagonist) in the presence of 1 mM NiCl2 was five times higher than the previously reported values obtained in the absence of NiCl2 (Kitada, 1991). Ni2+ ions at 1 mM enhanced the maximal response to Na+ ions by 190%. It appears that a sodium receptor (or channel) interacts with a Ni2+-binding element that is affected by Ni2+ ions and, thus, Ni2+ ions can induce both an increase in the affinity of the sodium receptor for the respective cations and an enhancement of the Na+ response.

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