PMID- 1844564
OWN - NLM
STAT- MEDLINE
DCOM- 19930519
LR  - 20131121
IS  - 1015-3845 (Print)
IS  - 1015-3845 (Linking)
VI  - 10
IP  - 2-4
DP  - 1991-1992
TI  - Use of ion-sensitive microelectrodes to study intracellular free magnesium 
      concentration and its regulation in mammalian cardiac muscle.
PG  - 80-9
AB  - Ion-sensitive microelectrodes (ISEs) have been used to measure intracellular 
      [Mg2+] ([Mg2+]i) in cardiac muscle, although most measurements have tended to 
      overestimate the value due to the poor selectivity of the Mg2+ ionophore in the 
      sarcoplasm and to inaccurate collation of individual ISE measurements. This paper 
      highlights the correct method for analysis of data from multiple ISE experiments. 
      Since [Mg2+]i is constrained at a lower concentration than would be expected by 
      passive distribution of the ion, some of the possible mechanisms underlying Mg2+ 
      extrusion from ferret ventricular myocardium were investigated. During elevation 
      of the extracellular [Mg], mean [Mg2+]i rose from 1.61 to 1.91 mM. The same 
      intervention had no significant effect on membrane potential, intracellular [Na+] 
      or pH measured with ISEs, and there was no change in resting [Ca2+], as assessed 
      from fura-2 fluorescence. The data are not consistent with a simple mechanism for 
      Na(+)-Mg2+ exchange as the primary mode of Mg2+ regulation in cardiac muscle or 
      with an Mg2+ extrusion mechanism involving steady-state ion exchange.
FAU - Hall, S K
AU  - Hall SK
AD  - Sherrington School of Physiology, United Medical and Dental Schools (St. Thomas' 
      Campus), London, UK.
FAU - Fry, C H
AU  - Fry CH
FAU - Buri, A
AU  - Buri A
FAU - McGuigan, J A
AU  - McGuigan JA
LA  - eng
PT  - Journal Article
PL  - Switzerland
TA  - Magnes Trace Elem
JT  - Magnesium and trace elements
JID - 9005667
RN  - 0 (Ionophores)
RN  - 9NEZ333N27 (Sodium)
RN  - I38ZP9992A (Magnesium)
SB  - IM
MH  - Animals
MH  - Ferrets
MH  - Ion Transport/*physiology
MH  - Ionophores
MH  - Magnesium/*metabolism
MH  - Membrane Potentials
MH  - Microelectrodes
MH  - Myocardium/cytology/*metabolism
MH  - Sodium/metabolism
EDAT- 1991/01/01 00:00
MHDA- 1991/01/01 00:01
CRDT- 1991/01/01 00:00
PHST- 1991/01/01 00:00 [pubmed]
PHST- 1991/01/01 00:01 [medline]
PHST- 1991/01/01 00:00 [entrez]
PST - ppublish
SO  - Magnes Trace Elem. 1991-1992;10(2-4):80-9.