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

Ingemansson, Max LU ; Arlock, P and Olsson, Bertil LU (1998) In Acta Physiologica Scandinavica 164(2). p.173-179
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... (More)
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 glucose alone or in combination with insulin. The effects of [Mg2+]o in combination with the GIK solutions on action potential parameters seemed to be attributable to the supernormal [Mg2+]o and [K+]o alone, while these seemed to have opposite effects on APD90. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
action potential duration, atrial fibrillation, magnesium, polarizing solution, resting potential
in
Acta Physiologica Scandinavica
volume
164
issue
2
pages
173 - 179
publisher
Wiley-Blackwell
external identifiers
  • pmid:9805104
  • scopus:0031787116
ISSN
0001-6772
DOI
10.1046/j.1365-201X.1998.00414.x
language
English
LU publication?
yes
id
57785883-0ed6-4e3a-9981-94d9dbe67b9c (old id 1114024)
date added to LUP
2008-07-16 15:20:20
date last changed
2017-01-01 07:02:50
@article{57785883-0ed6-4e3a-9981-94d9dbe67b9c,
  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 glucose alone or in combination with insulin. The effects of [Mg2+]o in combination with the GIK solutions on action potential parameters seemed to be attributable to the supernormal [Mg2+]o and [K+]o alone, while these seemed to have opposite effects on APD90.},
  author       = {Ingemansson, Max and Arlock, P and Olsson, Bertil},
  issn         = {0001-6772},
  keyword      = {action potential duration,atrial fibrillation,magnesium,polarizing solution,resting potential},
  language     = {eng},
  number       = {2},
  pages        = {173--179},
  publisher    = {Wiley-Blackwell},
  series       = {Acta Physiologica Scandinavica},
  title        = {Effects of magnesium and glucose, insulin, potassium (GIK) solution on the action potential parameters of guinea-pig atrial muscle},
  url          = {http://dx.doi.org/10.1046/j.1365-201X.1998.00414.x},
  volume       = {164},
  year         = {1998},
}