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The Actions of Extracellular Magnesium on Isolated Human Detrusor Muscle Function
Author(s) -
MONTGOMERY B. S. I.,
THOMAS P. J.,
FRY C. H.
Publication year - 1992
Publication title -
british journal of urology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.773
H-Index - 148
eISSN - 1464-410X
pISSN - 0007-1331
DOI - 10.1111/j.1464-410x.1992.tb15728.x
Subject(s) - extracellular , detrusor muscle , intracellular , chemistry , magnesium , electrophysiology , biophysics , muscle contraction , medicine , endocrinology , smooth muscle , biology , biochemistry , organic chemistry
Summary— The effects of increasing the extracellular magnesium concentration ([Mg]) on the in vitro mechanical and electrophysiological properties of isolated human detrusor smooth muscle have been investigated. Raising extracellular Mg reduced the magnitude of the electrically‐induced phasic contractions as well as spontaneous contractions. A similar increase in the [Mg] reduced the magnitude of the inward Ca 2+ current associated with the action potential as well as shifting the activation curve to more positive potentials. Spontaneous oscillations of intracellular Ca 2+ could be observed in some isolated cells and such activity was also abolished by raising the extracellular [Mg]. It is proposed that the contractile effects of raised extracellular Mg are mediated by an action on the inward Ca 2+ current and that these observations suggest a means whereby normal and abnormal detrusor contractions might be effectively regulated.