Effect of subtype-specific Ca2+-antagonists and Ca2+-free media on the field stimulation-evoked release of ATP and [3H]acetylcholine from rat habenula slices

B. Sperlágh, Ibolya András, E. Vízi

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11 Citations (Scopus)

Abstract

The involvement of different subtypes of voltage-sensitive Ca2+ channels in the initiation of field stimulation-induced endogenous adenosine triphosphate (ATP) and [3H]acetylcholine ([3H]ACh) release was investigated in the superfused rat habenula slices. ATP, measured by the luciferin- luciferase assay, and [3H]ACh were released simultaneously from the tissue in response to low frequency electrical stimulation (2 Hz, 2.5 msec, 360 shocks). The N-type Ca2+ channel blocker ω-conotoxin GVIA (ω-CgTX, 0.01- 1 μM) reduced the stimulation-evoked release of ATP and [3H]ACh in a dose- dependent manner. Similarly, the P-type Ca2+ channel antagonist ω-agatoxin IVA (ω-Aga IVA) (0.05 μM) and the inorganic Ca2+ channel blocker Cd2+ (0.2 mM) inhibited the outflow of both transmitters, while Ni2+ (0.1 mM) was without significant effect. A high correlation was observed between the percent inhibition of ATP release and percent inhibition of ACh release caused by the different Ca2+ antagonists. Long-term perfusion (i.e., 90 min) with Ca2+ free solution inhibited the evoked-release of ATP and [3H]ACh. In contrast, perfusion of slices with the same media for a shorter time (i.e., 20 min) did not reduce the release of [3H]ACh and ATP but even increased the evoked-release of ATP about fourfold. The breakdown of extracellular ATP was not blocked under low [Ca2+]0 condition, measured by the creatine phosphokinase assay and HPLC-UV technique. Application of extra- or intracellular Ca2+ chelators, and dipyridamole (2 μM), the nucleoside transporter inhibitor, did not reduce the excess release of ATP after short- term perfusion with Ca2+-free media. Tetrodotoxin (TTX, 1 μM), while inhibiting the majority of ATP release under normal conditions, was also unable to reduce release under low [Ca2+]0 conditions. In summary, we showed that both N- and P-type Ca2+ channels are involved in the initiation of electrical stimulation-evoked release of ATP and [3H]ACh in the rat habenula under normal extracellular calcium concentration. Under low [Ca2+]0 conditions an additional release of ATP occurs, which is not associated with action potential propagation.

Original languageEnglish
Pages (from-to)967-975
Number of pages9
JournalNeurochemical Research
Volume22
Issue number8
DOIs
Publication statusPublished - 1997

Fingerprint

Habenula
Acetylcholine
Rats
Adenosine Triphosphate
Perfusion
Electric Stimulation
Assays
Agatoxins
Conotoxins
Nucleoside Transport Proteins
Dipyridamole
Tetrodotoxin
Creatine Kinase
Chelating Agents
Luciferases
Action Potentials
Transmitters
Shock

Keywords

  • Acetylcholine
  • ATP
  • Ca channels
  • Habenula
  • Release

ASJC Scopus subject areas

  • Neuroscience(all)
  • Biochemistry

Cite this

@article{bb0e512d07004b57b59c874ae78fac09,
title = "Effect of subtype-specific Ca2+-antagonists and Ca2+-free media on the field stimulation-evoked release of ATP and [3H]acetylcholine from rat habenula slices",
abstract = "The involvement of different subtypes of voltage-sensitive Ca2+ channels in the initiation of field stimulation-induced endogenous adenosine triphosphate (ATP) and [3H]acetylcholine ([3H]ACh) release was investigated in the superfused rat habenula slices. ATP, measured by the luciferin- luciferase assay, and [3H]ACh were released simultaneously from the tissue in response to low frequency electrical stimulation (2 Hz, 2.5 msec, 360 shocks). The N-type Ca2+ channel blocker ω-conotoxin GVIA (ω-CgTX, 0.01- 1 μM) reduced the stimulation-evoked release of ATP and [3H]ACh in a dose- dependent manner. Similarly, the P-type Ca2+ channel antagonist ω-agatoxin IVA (ω-Aga IVA) (0.05 μM) and the inorganic Ca2+ channel blocker Cd2+ (0.2 mM) inhibited the outflow of both transmitters, while Ni2+ (0.1 mM) was without significant effect. A high correlation was observed between the percent inhibition of ATP release and percent inhibition of ACh release caused by the different Ca2+ antagonists. Long-term perfusion (i.e., 90 min) with Ca2+ free solution inhibited the evoked-release of ATP and [3H]ACh. In contrast, perfusion of slices with the same media for a shorter time (i.e., 20 min) did not reduce the release of [3H]ACh and ATP but even increased the evoked-release of ATP about fourfold. The breakdown of extracellular ATP was not blocked under low [Ca2+]0 condition, measured by the creatine phosphokinase assay and HPLC-UV technique. Application of extra- or intracellular Ca2+ chelators, and dipyridamole (2 μM), the nucleoside transporter inhibitor, did not reduce the excess release of ATP after short- term perfusion with Ca2+-free media. Tetrodotoxin (TTX, 1 μM), while inhibiting the majority of ATP release under normal conditions, was also unable to reduce release under low [Ca2+]0 conditions. In summary, we showed that both N- and P-type Ca2+ channels are involved in the initiation of electrical stimulation-evoked release of ATP and [3H]ACh in the rat habenula under normal extracellular calcium concentration. Under low [Ca2+]0 conditions an additional release of ATP occurs, which is not associated with action potential propagation.",
keywords = "Acetylcholine, ATP, Ca channels, Habenula, Release",
author = "B. Sperl{\'a}gh and Ibolya Andr{\'a}s and E. V{\'i}zi",
year = "1997",
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language = "English",
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journal = "Neurochemical Research",
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TY - JOUR

T1 - Effect of subtype-specific Ca2+-antagonists and Ca2+-free media on the field stimulation-evoked release of ATP and [3H]acetylcholine from rat habenula slices

AU - Sperlágh, B.

AU - András, Ibolya

AU - Vízi, E.

PY - 1997

Y1 - 1997

N2 - The involvement of different subtypes of voltage-sensitive Ca2+ channels in the initiation of field stimulation-induced endogenous adenosine triphosphate (ATP) and [3H]acetylcholine ([3H]ACh) release was investigated in the superfused rat habenula slices. ATP, measured by the luciferin- luciferase assay, and [3H]ACh were released simultaneously from the tissue in response to low frequency electrical stimulation (2 Hz, 2.5 msec, 360 shocks). The N-type Ca2+ channel blocker ω-conotoxin GVIA (ω-CgTX, 0.01- 1 μM) reduced the stimulation-evoked release of ATP and [3H]ACh in a dose- dependent manner. Similarly, the P-type Ca2+ channel antagonist ω-agatoxin IVA (ω-Aga IVA) (0.05 μM) and the inorganic Ca2+ channel blocker Cd2+ (0.2 mM) inhibited the outflow of both transmitters, while Ni2+ (0.1 mM) was without significant effect. A high correlation was observed between the percent inhibition of ATP release and percent inhibition of ACh release caused by the different Ca2+ antagonists. Long-term perfusion (i.e., 90 min) with Ca2+ free solution inhibited the evoked-release of ATP and [3H]ACh. In contrast, perfusion of slices with the same media for a shorter time (i.e., 20 min) did not reduce the release of [3H]ACh and ATP but even increased the evoked-release of ATP about fourfold. The breakdown of extracellular ATP was not blocked under low [Ca2+]0 condition, measured by the creatine phosphokinase assay and HPLC-UV technique. Application of extra- or intracellular Ca2+ chelators, and dipyridamole (2 μM), the nucleoside transporter inhibitor, did not reduce the excess release of ATP after short- term perfusion with Ca2+-free media. Tetrodotoxin (TTX, 1 μM), while inhibiting the majority of ATP release under normal conditions, was also unable to reduce release under low [Ca2+]0 conditions. In summary, we showed that both N- and P-type Ca2+ channels are involved in the initiation of electrical stimulation-evoked release of ATP and [3H]ACh in the rat habenula under normal extracellular calcium concentration. Under low [Ca2+]0 conditions an additional release of ATP occurs, which is not associated with action potential propagation.

AB - The involvement of different subtypes of voltage-sensitive Ca2+ channels in the initiation of field stimulation-induced endogenous adenosine triphosphate (ATP) and [3H]acetylcholine ([3H]ACh) release was investigated in the superfused rat habenula slices. ATP, measured by the luciferin- luciferase assay, and [3H]ACh were released simultaneously from the tissue in response to low frequency electrical stimulation (2 Hz, 2.5 msec, 360 shocks). The N-type Ca2+ channel blocker ω-conotoxin GVIA (ω-CgTX, 0.01- 1 μM) reduced the stimulation-evoked release of ATP and [3H]ACh in a dose- dependent manner. Similarly, the P-type Ca2+ channel antagonist ω-agatoxin IVA (ω-Aga IVA) (0.05 μM) and the inorganic Ca2+ channel blocker Cd2+ (0.2 mM) inhibited the outflow of both transmitters, while Ni2+ (0.1 mM) was without significant effect. A high correlation was observed between the percent inhibition of ATP release and percent inhibition of ACh release caused by the different Ca2+ antagonists. Long-term perfusion (i.e., 90 min) with Ca2+ free solution inhibited the evoked-release of ATP and [3H]ACh. In contrast, perfusion of slices with the same media for a shorter time (i.e., 20 min) did not reduce the release of [3H]ACh and ATP but even increased the evoked-release of ATP about fourfold. The breakdown of extracellular ATP was not blocked under low [Ca2+]0 condition, measured by the creatine phosphokinase assay and HPLC-UV technique. Application of extra- or intracellular Ca2+ chelators, and dipyridamole (2 μM), the nucleoside transporter inhibitor, did not reduce the excess release of ATP after short- term perfusion with Ca2+-free media. Tetrodotoxin (TTX, 1 μM), while inhibiting the majority of ATP release under normal conditions, was also unable to reduce release under low [Ca2+]0 conditions. In summary, we showed that both N- and P-type Ca2+ channels are involved in the initiation of electrical stimulation-evoked release of ATP and [3H]ACh in the rat habenula under normal extracellular calcium concentration. Under low [Ca2+]0 conditions an additional release of ATP occurs, which is not associated with action potential propagation.

KW - Acetylcholine

KW - ATP

KW - Ca channels

KW - Habenula

KW - Release

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