Nov 7, 1998

Effects of magnesium and glucose, insulin, potassium (GIK) solution on the action potential parameters of guinea-pig atrial muscle

Acta Physiologica Scandinavica
M IngemanssonS B Olsson

Abstract

The present paper aims to explore the effects of [Mg2+]o and glucose, insulin and K+ (GIK) on action potential parameters in guinea-pig atrial muscle. Specimens of atrial appendages were taken from guinea-pig hearts. Action potentials were recorded in isolated atrial trabeculae. Resting potential (RP) and action potential duration at 90% repolarization (APD90) were measured with conventional microelectrode techniques. [Mg2+]o at 6 and 12 mmol L-1 depolarized the RP and prolonged the APD90, whereas 4 mmol L-1 had no effect at all. Glucose alone or in combination with insulin had no effect on action potential parameters. GIK solution with supernormal [K+]o at 6 mmol L-1 depolarized the RP and decreased the APD90. Intervention with [Mg2+]o at 4 mmol L-1 in combination with GIK solution with supernormal [K+]o of 6 mmol L-1, reversibly depolarized the RP, whereas the APD90 was not significantly changed. [Mg2+]o at 12 mmol L-1 in combination with GIK solution with a physiological [K+]o of 4 mmol L-1 prolonged the APD90 whereas the RP was unaffected. [Mg2+]o at 6 and 12 mmol L-1 slightly depolarized the RP and prolonged the APD90. The action potential of normally polarized atrial muscle was not sensitive to supernormal levels of gluco...Continue Reading

  • References23
  • Citations1

Mentioned in this Paper

Potassium
Glucose, (beta-D)-Isomer
Right Atrial Structure
Atrial Function
Tremor
Novolin
Skeletal Myocytes
Heart
Nerve Impulses
Cavia porcellus

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