Role of intracellular calcium in peroxide-induced potentiation of norepinephrine release from bovine irides

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Abstract

Both natural and synthetic peroxides have been shown to enhance sympathetic neurotransmission in the bovine isolated iris (Opere et al., IOVS 37: No. 2663, 1996). Purpose. To investigate the role of intracellular calcium ([Ca++]i) in peroxide-induced potentiation of adrenergic ncurosecretion from the bovine iris. Methods. Herni-irides were isolated from bovine eyeballs and prepared for studies of field-stimulated [3H]-norepinephrine ([3H]NE) release using the supervision method. Results. Regulators of [Ca++], such as BAPTA AM (10 μM), thapsigargin (THAP, 10 MM), ruthenium red (RR, 30 μM) and oligomycin (OLIGO, 30 μM) inhibited electrically-evoked [3H]NE overflow bv 54%, 30%, 30% and 26%, lespectively. H2O2 (0.3 mM) produced a 42% increase in evoked [3H|NE release that was blocked bv RR (30 μM). Conversely, OLIGO (30 μM) potentiated H2O2 (0-3 mM)-induced enhancement of field-stimulated [3H]NE overflow bv 89%. Interestingly, both BAPTA AM (10 μM) and THAP (10 μM) had no effect on the peroxide response. Conclusions. Mitochondrial Ca++ stores are involved in H2O2,-induced potentiation of stimulated |3H]NE release. However, changes in both eytosolic and endoplasmic reticulum Ca++ stores may not affect peroxide-induced enhancement of sympathetic neurotransmission in the bovine iris.

Original languageEnglish
JournalInvestigative Ophthalmology and Visual Science
Volume38
Issue number4
StatePublished - 1997

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Peroxides
Iris
Norepinephrine
Synaptic Transmission
Oligomycins
Ruthenium Red
Thapsigargin
Endoplasmic Reticulum
Adrenergic Agents
Calcium
calcium peroxide
1,2-bis(2-aminophenoxy)ethane N,N,N',N'-tetraacetic acid acetoxymethyl ester

All Science Journal Classification (ASJC) codes

  • Ophthalmology

Cite this

@article{10fbde82aaac44f883c422976f598959,
title = "Role of intracellular calcium in peroxide-induced potentiation of norepinephrine release from bovine irides",
abstract = "Both natural and synthetic peroxides have been shown to enhance sympathetic neurotransmission in the bovine isolated iris (Opere et al., IOVS 37: No. 2663, 1996). Purpose. To investigate the role of intracellular calcium ([Ca++]i) in peroxide-induced potentiation of adrenergic ncurosecretion from the bovine iris. Methods. Herni-irides were isolated from bovine eyeballs and prepared for studies of field-stimulated [3H]-norepinephrine ([3H]NE) release using the supervision method. Results. Regulators of [Ca++], such as BAPTA AM (10 μM), thapsigargin (THAP, 10 MM), ruthenium red (RR, 30 μM) and oligomycin (OLIGO, 30 μM) inhibited electrically-evoked [3H]NE overflow bv 54{\%}, 30{\%}, 30{\%} and 26{\%}, lespectively. H2O2 (0.3 mM) produced a 42{\%} increase in evoked [3H|NE release that was blocked bv RR (30 μM). Conversely, OLIGO (30 μM) potentiated H2O2 (0-3 mM)-induced enhancement of field-stimulated [3H]NE overflow bv 89{\%}. Interestingly, both BAPTA AM (10 μM) and THAP (10 μM) had no effect on the peroxide response. Conclusions. Mitochondrial Ca++ stores are involved in H2O2,-induced potentiation of stimulated |3H]NE release. However, changes in both eytosolic and endoplasmic reticulum Ca++ stores may not affect peroxide-induced enhancement of sympathetic neurotransmission in the bovine iris.",
author = "Opere, {Catherine A.} and S. Ohia",
year = "1997",
language = "English",
volume = "38",
journal = "Investigative Ophthalmology and Visual Science",
issn = "0146-0404",
publisher = "Association for Research in Vision and Ophthalmology Inc.",
number = "4",

}

TY - JOUR

T1 - Role of intracellular calcium in peroxide-induced potentiation of norepinephrine release from bovine irides

AU - Opere, Catherine A.

AU - Ohia, S.

PY - 1997

Y1 - 1997

N2 - Both natural and synthetic peroxides have been shown to enhance sympathetic neurotransmission in the bovine isolated iris (Opere et al., IOVS 37: No. 2663, 1996). Purpose. To investigate the role of intracellular calcium ([Ca++]i) in peroxide-induced potentiation of adrenergic ncurosecretion from the bovine iris. Methods. Herni-irides were isolated from bovine eyeballs and prepared for studies of field-stimulated [3H]-norepinephrine ([3H]NE) release using the supervision method. Results. Regulators of [Ca++], such as BAPTA AM (10 μM), thapsigargin (THAP, 10 MM), ruthenium red (RR, 30 μM) and oligomycin (OLIGO, 30 μM) inhibited electrically-evoked [3H]NE overflow bv 54%, 30%, 30% and 26%, lespectively. H2O2 (0.3 mM) produced a 42% increase in evoked [3H|NE release that was blocked bv RR (30 μM). Conversely, OLIGO (30 μM) potentiated H2O2 (0-3 mM)-induced enhancement of field-stimulated [3H]NE overflow bv 89%. Interestingly, both BAPTA AM (10 μM) and THAP (10 μM) had no effect on the peroxide response. Conclusions. Mitochondrial Ca++ stores are involved in H2O2,-induced potentiation of stimulated |3H]NE release. However, changes in both eytosolic and endoplasmic reticulum Ca++ stores may not affect peroxide-induced enhancement of sympathetic neurotransmission in the bovine iris.

AB - Both natural and synthetic peroxides have been shown to enhance sympathetic neurotransmission in the bovine isolated iris (Opere et al., IOVS 37: No. 2663, 1996). Purpose. To investigate the role of intracellular calcium ([Ca++]i) in peroxide-induced potentiation of adrenergic ncurosecretion from the bovine iris. Methods. Herni-irides were isolated from bovine eyeballs and prepared for studies of field-stimulated [3H]-norepinephrine ([3H]NE) release using the supervision method. Results. Regulators of [Ca++], such as BAPTA AM (10 μM), thapsigargin (THAP, 10 MM), ruthenium red (RR, 30 μM) and oligomycin (OLIGO, 30 μM) inhibited electrically-evoked [3H]NE overflow bv 54%, 30%, 30% and 26%, lespectively. H2O2 (0.3 mM) produced a 42% increase in evoked [3H|NE release that was blocked bv RR (30 μM). Conversely, OLIGO (30 μM) potentiated H2O2 (0-3 mM)-induced enhancement of field-stimulated [3H]NE overflow bv 89%. Interestingly, both BAPTA AM (10 μM) and THAP (10 μM) had no effect on the peroxide response. Conclusions. Mitochondrial Ca++ stores are involved in H2O2,-induced potentiation of stimulated |3H]NE release. However, changes in both eytosolic and endoplasmic reticulum Ca++ stores may not affect peroxide-induced enhancement of sympathetic neurotransmission in the bovine iris.

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VL - 38

JO - Investigative Ophthalmology and Visual Science

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