Electrical and mechanical effects of strontium in sheep cardiac purkinje fibres

Mario Gonzalez, Mario Vassalle

Research output: Contribution to journalReview article

6 Citations (Scopus)

Abstract

The electrical and mechanical effects of strontium were studied in sheep cardiac Purkinje fibres perfused in vitro. In a nominally calcium free solution, strontium (1.35-10.8 mmol·litre-1): (1) caused a time, rate and concentration dependent shift of the plateau to more positive potentials, prolonged the action potential and decreased the maximum diastolic potential; (2) increased the time to peak and amplitude of the twitch and caused a tonic force which relaxed only on repolarisation; (3) was rapidly overcome in its effects by calcium (1.35-2.7 mmol·litre-1); (4) was antagonised by manganese (1 mmol·litre-1) and cadmium (0.1-0.2 mmol·litre-1); (5) was potentiated by noradrenaline (0.1 μmol·litre-1); (6) could induce action potentials in 27 mmol·litre-1 [K]o; (7) induced a tail following the action potential when the pacemaker potential had been blocked by caesium; (8) could induce a tail in 8 mmol·litre-1 [K]o which sustained force development and was reduced by calcium antagonists; (9) if applied to a quiescent fibre, induced a prolongation of the first resumed action potential and tonic force but a small twitch, and these effects were antagonised by calcium and manganese; and (10) induced a strong twitch after a period of quiescence in low [Na]o. It is concluded that the pronounced and progressive electrical and mechanical effects of strontium in cardiac Purkinje fibres are due to an enhanced strontium influx (due to inability of strontium to substitute for calcium in the inactivation of Isi) and to strontium extrusion through an electrogenic Na-Sr exchange.

Original languageEnglish (US)
Pages (from-to)867-881
Number of pages15
JournalCardiovascular Research
Volume23
Issue number10
DOIs
StatePublished - Jan 1 1989

Fingerprint

Purkinje Fibers
Strontium
Sheep
Action Potentials
Calcium
Manganese
Tail
Cesium
Cadmium
Norepinephrine

All Science Journal Classification (ASJC) codes

  • Physiology
  • Cardiology and Cardiovascular Medicine
  • Physiology (medical)

Cite this

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title = "Electrical and mechanical effects of strontium in sheep cardiac purkinje fibres",
abstract = "The electrical and mechanical effects of strontium were studied in sheep cardiac Purkinje fibres perfused in vitro. In a nominally calcium free solution, strontium (1.35-10.8 mmol·litre-1): (1) caused a time, rate and concentration dependent shift of the plateau to more positive potentials, prolonged the action potential and decreased the maximum diastolic potential; (2) increased the time to peak and amplitude of the twitch and caused a tonic force which relaxed only on repolarisation; (3) was rapidly overcome in its effects by calcium (1.35-2.7 mmol·litre-1); (4) was antagonised by manganese (1 mmol·litre-1) and cadmium (0.1-0.2 mmol·litre-1); (5) was potentiated by noradrenaline (0.1 μmol·litre-1); (6) could induce action potentials in 27 mmol·litre-1 [K]o; (7) induced a tail following the action potential when the pacemaker potential had been blocked by caesium; (8) could induce a tail in 8 mmol·litre-1 [K]o which sustained force development and was reduced by calcium antagonists; (9) if applied to a quiescent fibre, induced a prolongation of the first resumed action potential and tonic force but a small twitch, and these effects were antagonised by calcium and manganese; and (10) induced a strong twitch after a period of quiescence in low [Na]o. It is concluded that the pronounced and progressive electrical and mechanical effects of strontium in cardiac Purkinje fibres are due to an enhanced strontium influx (due to inability of strontium to substitute for calcium in the inactivation of Isi) and to strontium extrusion through an electrogenic Na-Sr exchange.",
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Electrical and mechanical effects of strontium in sheep cardiac purkinje fibres. / Gonzalez, Mario; Vassalle, Mario.

In: Cardiovascular Research, Vol. 23, No. 10, 01.01.1989, p. 867-881.

Research output: Contribution to journalReview article

TY - JOUR

T1 - Electrical and mechanical effects of strontium in sheep cardiac purkinje fibres

AU - Gonzalez, Mario

AU - Vassalle, Mario

PY - 1989/1/1

Y1 - 1989/1/1

N2 - The electrical and mechanical effects of strontium were studied in sheep cardiac Purkinje fibres perfused in vitro. In a nominally calcium free solution, strontium (1.35-10.8 mmol·litre-1): (1) caused a time, rate and concentration dependent shift of the plateau to more positive potentials, prolonged the action potential and decreased the maximum diastolic potential; (2) increased the time to peak and amplitude of the twitch and caused a tonic force which relaxed only on repolarisation; (3) was rapidly overcome in its effects by calcium (1.35-2.7 mmol·litre-1); (4) was antagonised by manganese (1 mmol·litre-1) and cadmium (0.1-0.2 mmol·litre-1); (5) was potentiated by noradrenaline (0.1 μmol·litre-1); (6) could induce action potentials in 27 mmol·litre-1 [K]o; (7) induced a tail following the action potential when the pacemaker potential had been blocked by caesium; (8) could induce a tail in 8 mmol·litre-1 [K]o which sustained force development and was reduced by calcium antagonists; (9) if applied to a quiescent fibre, induced a prolongation of the first resumed action potential and tonic force but a small twitch, and these effects were antagonised by calcium and manganese; and (10) induced a strong twitch after a period of quiescence in low [Na]o. It is concluded that the pronounced and progressive electrical and mechanical effects of strontium in cardiac Purkinje fibres are due to an enhanced strontium influx (due to inability of strontium to substitute for calcium in the inactivation of Isi) and to strontium extrusion through an electrogenic Na-Sr exchange.

AB - The electrical and mechanical effects of strontium were studied in sheep cardiac Purkinje fibres perfused in vitro. In a nominally calcium free solution, strontium (1.35-10.8 mmol·litre-1): (1) caused a time, rate and concentration dependent shift of the plateau to more positive potentials, prolonged the action potential and decreased the maximum diastolic potential; (2) increased the time to peak and amplitude of the twitch and caused a tonic force which relaxed only on repolarisation; (3) was rapidly overcome in its effects by calcium (1.35-2.7 mmol·litre-1); (4) was antagonised by manganese (1 mmol·litre-1) and cadmium (0.1-0.2 mmol·litre-1); (5) was potentiated by noradrenaline (0.1 μmol·litre-1); (6) could induce action potentials in 27 mmol·litre-1 [K]o; (7) induced a tail following the action potential when the pacemaker potential had been blocked by caesium; (8) could induce a tail in 8 mmol·litre-1 [K]o which sustained force development and was reduced by calcium antagonists; (9) if applied to a quiescent fibre, induced a prolongation of the first resumed action potential and tonic force but a small twitch, and these effects were antagonised by calcium and manganese; and (10) induced a strong twitch after a period of quiescence in low [Na]o. It is concluded that the pronounced and progressive electrical and mechanical effects of strontium in cardiac Purkinje fibres are due to an enhanced strontium influx (due to inability of strontium to substitute for calcium in the inactivation of Isi) and to strontium extrusion through an electrogenic Na-Sr exchange.

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U2 - 10.1093/cvr/23.10.867

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