Pharmacological blockade of ERG K+ channels and Ca2+ influx through store-operated channels exerts opposite effects on intracellular Ca2+ oscillations in pituitary GH3 cells

Agnese Secondo, Maurizio Taglialatela, Mauro Cataldi, Giovanna Giorgio, Monica Valore, Gianfranco Di Renzo, Lucio Annunziato

Research output: Contribution to journalArticle

29 Citations (Scopus)

Abstract

In the present study, the effects on intracellular calcium concentration ([Ca2+](i)) oscillations of the blockade of ether-a-go-go-related gene (ERG) K+ channels and of Ca2+ influx through store-operated channels (SOC) activated by [Ca2+](i) store depletion have been studied in GH3 cells by means of a combination of single-cell fura-2 microfluorimetry and whole-cell mode of the patch-clamp technique. Nanomolar concentrations (1-30 nM) of the piperidinic second-generation antihistamines terfenadine and astemizole and of the class III antiarrhythmic methanesulfonanilide dofetilide, by blocking ERG K+ channels, increased the frequency and the amplitude of [Ca2+](i) oscillations in resting oscillating GH3 cells. These compounds also induced the appearance of an oscillatory pattern of [Ca2+](i) in a subpopulation of nonoscillating GH3 cells. The effects of ERG K+ channel blockade on [Ca2+](i) oscillations appeared to be due to the activation of L-type Ca2+ channels, because they were prevented by 300 nM nimodipine. By contrast, the piperazinic second-generation antihistamine cetirizine (0.01-30 μM), which served as a negative control, failed to affect ERG K+ channels and did not interfere with [Ca2+](i) oscillations in GH3 cells. Interestingly, micromolar concentrations of terfenadine and astemizole (0.3-30 μM), but not of dofetilide (10-100 μM), produced an inhibition of the spontaneous oscillatory pattern of [Ca2+](i) changes. This effect was possibly related to an inhibition of SOC, because these compounds inhibited the increase of [Ca2+](i) achieved by extracellular calcium reintroduction after intracellular calcium store depletion with the sarcoplasmic or endoplasmic reticulum calcium ATPase pump inhibitor thapsigargin (10 μM) in an extracellular calcium-free medium. The same inhibitory effect on [Ca2+](i) oscillations and SOC was observed with the first-generation antihistamine hydroxyzine (1-30 μM), the more hydrophobic metabolic precursor of cetirizine. Collectively, the results of the present study obtained with compounds that interfere in a different concentration range with ERG K+ channels or SOC suggest that 1) ERG K+ channels play a relevant role in controlling the oscillatory pattern of [Ca2+](i) in resting GH3 cells and 2) the inhibition of SOC might induce an opposite effect, i.e., an inhibition of [Ca2+](i) oscillations.

Original languageEnglish
Pages (from-to)1115-1128
Number of pages14
JournalMolecular Pharmacology
Volume58
Issue number5
Publication statusPublished - 2000

Fingerprint

Pharmacology
Non-Sedating Histamine H1 Antagonists
Astemizole
Cetirizine
Terfenadine
Calcium
Hydroxyzine
Cytophotometry
Nimodipine
Thapsigargin
Calcium-Transporting ATPases
Fura-2
Histamine Antagonists
Sarcoplasmic Reticulum
Patch-Clamp Techniques
Endoplasmic Reticulum
Ether
Genes
dofetilide

ASJC Scopus subject areas

  • Pharmacology

Cite this

Pharmacological blockade of ERG K+ channels and Ca2+ influx through store-operated channels exerts opposite effects on intracellular Ca2+ oscillations in pituitary GH3 cells. / Secondo, Agnese; Taglialatela, Maurizio; Cataldi, Mauro; Giorgio, Giovanna; Valore, Monica; Di Renzo, Gianfranco; Annunziato, Lucio.

In: Molecular Pharmacology, Vol. 58, No. 5, 2000, p. 1115-1128.

Research output: Contribution to journalArticle

Secondo, Agnese ; Taglialatela, Maurizio ; Cataldi, Mauro ; Giorgio, Giovanna ; Valore, Monica ; Di Renzo, Gianfranco ; Annunziato, Lucio. / Pharmacological blockade of ERG K+ channels and Ca2+ influx through store-operated channels exerts opposite effects on intracellular Ca2+ oscillations in pituitary GH3 cells. In: Molecular Pharmacology. 2000 ; Vol. 58, No. 5. pp. 1115-1128.
@article{e5ddb9c564234e829ed0760bb6c4baca,
title = "Pharmacological blockade of ERG K+ channels and Ca2+ influx through store-operated channels exerts opposite effects on intracellular Ca2+ oscillations in pituitary GH3 cells",
abstract = "In the present study, the effects on intracellular calcium concentration ([Ca2+](i)) oscillations of the blockade of ether-a-go-go-related gene (ERG) K+ channels and of Ca2+ influx through store-operated channels (SOC) activated by [Ca2+](i) store depletion have been studied in GH3 cells by means of a combination of single-cell fura-2 microfluorimetry and whole-cell mode of the patch-clamp technique. Nanomolar concentrations (1-30 nM) of the piperidinic second-generation antihistamines terfenadine and astemizole and of the class III antiarrhythmic methanesulfonanilide dofetilide, by blocking ERG K+ channels, increased the frequency and the amplitude of [Ca2+](i) oscillations in resting oscillating GH3 cells. These compounds also induced the appearance of an oscillatory pattern of [Ca2+](i) in a subpopulation of nonoscillating GH3 cells. The effects of ERG K+ channel blockade on [Ca2+](i) oscillations appeared to be due to the activation of L-type Ca2+ channels, because they were prevented by 300 nM nimodipine. By contrast, the piperazinic second-generation antihistamine cetirizine (0.01-30 μM), which served as a negative control, failed to affect ERG K+ channels and did not interfere with [Ca2+](i) oscillations in GH3 cells. Interestingly, micromolar concentrations of terfenadine and astemizole (0.3-30 μM), but not of dofetilide (10-100 μM), produced an inhibition of the spontaneous oscillatory pattern of [Ca2+](i) changes. This effect was possibly related to an inhibition of SOC, because these compounds inhibited the increase of [Ca2+](i) achieved by extracellular calcium reintroduction after intracellular calcium store depletion with the sarcoplasmic or endoplasmic reticulum calcium ATPase pump inhibitor thapsigargin (10 μM) in an extracellular calcium-free medium. The same inhibitory effect on [Ca2+](i) oscillations and SOC was observed with the first-generation antihistamine hydroxyzine (1-30 μM), the more hydrophobic metabolic precursor of cetirizine. Collectively, the results of the present study obtained with compounds that interfere in a different concentration range with ERG K+ channels or SOC suggest that 1) ERG K+ channels play a relevant role in controlling the oscillatory pattern of [Ca2+](i) in resting GH3 cells and 2) the inhibition of SOC might induce an opposite effect, i.e., an inhibition of [Ca2+](i) oscillations.",
author = "Agnese Secondo and Maurizio Taglialatela and Mauro Cataldi and Giovanna Giorgio and Monica Valore and {Di Renzo}, Gianfranco and Lucio Annunziato",
year = "2000",
language = "English",
volume = "58",
pages = "1115--1128",
journal = "Molecular Pharmacology",
issn = "0026-895X",
publisher = "American Society for Pharmacology and Experimental Therapeutics",
number = "5",

}

TY - JOUR

T1 - Pharmacological blockade of ERG K+ channels and Ca2+ influx through store-operated channels exerts opposite effects on intracellular Ca2+ oscillations in pituitary GH3 cells

AU - Secondo, Agnese

AU - Taglialatela, Maurizio

AU - Cataldi, Mauro

AU - Giorgio, Giovanna

AU - Valore, Monica

AU - Di Renzo, Gianfranco

AU - Annunziato, Lucio

PY - 2000

Y1 - 2000

N2 - In the present study, the effects on intracellular calcium concentration ([Ca2+](i)) oscillations of the blockade of ether-a-go-go-related gene (ERG) K+ channels and of Ca2+ influx through store-operated channels (SOC) activated by [Ca2+](i) store depletion have been studied in GH3 cells by means of a combination of single-cell fura-2 microfluorimetry and whole-cell mode of the patch-clamp technique. Nanomolar concentrations (1-30 nM) of the piperidinic second-generation antihistamines terfenadine and astemizole and of the class III antiarrhythmic methanesulfonanilide dofetilide, by blocking ERG K+ channels, increased the frequency and the amplitude of [Ca2+](i) oscillations in resting oscillating GH3 cells. These compounds also induced the appearance of an oscillatory pattern of [Ca2+](i) in a subpopulation of nonoscillating GH3 cells. The effects of ERG K+ channel blockade on [Ca2+](i) oscillations appeared to be due to the activation of L-type Ca2+ channels, because they were prevented by 300 nM nimodipine. By contrast, the piperazinic second-generation antihistamine cetirizine (0.01-30 μM), which served as a negative control, failed to affect ERG K+ channels and did not interfere with [Ca2+](i) oscillations in GH3 cells. Interestingly, micromolar concentrations of terfenadine and astemizole (0.3-30 μM), but not of dofetilide (10-100 μM), produced an inhibition of the spontaneous oscillatory pattern of [Ca2+](i) changes. This effect was possibly related to an inhibition of SOC, because these compounds inhibited the increase of [Ca2+](i) achieved by extracellular calcium reintroduction after intracellular calcium store depletion with the sarcoplasmic or endoplasmic reticulum calcium ATPase pump inhibitor thapsigargin (10 μM) in an extracellular calcium-free medium. The same inhibitory effect on [Ca2+](i) oscillations and SOC was observed with the first-generation antihistamine hydroxyzine (1-30 μM), the more hydrophobic metabolic precursor of cetirizine. Collectively, the results of the present study obtained with compounds that interfere in a different concentration range with ERG K+ channels or SOC suggest that 1) ERG K+ channels play a relevant role in controlling the oscillatory pattern of [Ca2+](i) in resting GH3 cells and 2) the inhibition of SOC might induce an opposite effect, i.e., an inhibition of [Ca2+](i) oscillations.

AB - In the present study, the effects on intracellular calcium concentration ([Ca2+](i)) oscillations of the blockade of ether-a-go-go-related gene (ERG) K+ channels and of Ca2+ influx through store-operated channels (SOC) activated by [Ca2+](i) store depletion have been studied in GH3 cells by means of a combination of single-cell fura-2 microfluorimetry and whole-cell mode of the patch-clamp technique. Nanomolar concentrations (1-30 nM) of the piperidinic second-generation antihistamines terfenadine and astemizole and of the class III antiarrhythmic methanesulfonanilide dofetilide, by blocking ERG K+ channels, increased the frequency and the amplitude of [Ca2+](i) oscillations in resting oscillating GH3 cells. These compounds also induced the appearance of an oscillatory pattern of [Ca2+](i) in a subpopulation of nonoscillating GH3 cells. The effects of ERG K+ channel blockade on [Ca2+](i) oscillations appeared to be due to the activation of L-type Ca2+ channels, because they were prevented by 300 nM nimodipine. By contrast, the piperazinic second-generation antihistamine cetirizine (0.01-30 μM), which served as a negative control, failed to affect ERG K+ channels and did not interfere with [Ca2+](i) oscillations in GH3 cells. Interestingly, micromolar concentrations of terfenadine and astemizole (0.3-30 μM), but not of dofetilide (10-100 μM), produced an inhibition of the spontaneous oscillatory pattern of [Ca2+](i) changes. This effect was possibly related to an inhibition of SOC, because these compounds inhibited the increase of [Ca2+](i) achieved by extracellular calcium reintroduction after intracellular calcium store depletion with the sarcoplasmic or endoplasmic reticulum calcium ATPase pump inhibitor thapsigargin (10 μM) in an extracellular calcium-free medium. The same inhibitory effect on [Ca2+](i) oscillations and SOC was observed with the first-generation antihistamine hydroxyzine (1-30 μM), the more hydrophobic metabolic precursor of cetirizine. Collectively, the results of the present study obtained with compounds that interfere in a different concentration range with ERG K+ channels or SOC suggest that 1) ERG K+ channels play a relevant role in controlling the oscillatory pattern of [Ca2+](i) in resting GH3 cells and 2) the inhibition of SOC might induce an opposite effect, i.e., an inhibition of [Ca2+](i) oscillations.

UR - http://www.scopus.com/inward/record.url?scp=0033790261&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0033790261&partnerID=8YFLogxK

M3 - Article

C2 - 11040061

AN - SCOPUS:0033790261

VL - 58

SP - 1115

EP - 1128

JO - Molecular Pharmacology

JF - Molecular Pharmacology

SN - 0026-895X

IS - 5

ER -