Intracellular alkalinization causes Mg2+ release from intracellular binding sites in leech Retzius neurones.
Pflugers Arch
; 435(1): 65-73, 1997 Dec.
Article
en En
| MEDLINE
| ID: mdl-9359904
ABSTRACT
Four-barrelled ion-sensitive microelectrodes were developed to enable simultaneous measurement of intracellular free Mg2+ and Na+ concentrations ([Mg2+]i, [Na+]i), intracellular pH and the membrane potential. The electrodes were used to investigate pH-induced [Mg2+]i changes in Retzius neurones of the leech Hirudo medicinalis. The application of propionate or CO2/HCO3--buffered bath solutions caused a transient intracellular acidification, an initial [Mg2+]i decrease and a continuous [Na+]i increase. In the presence of CO2/HCO3- this [Na+]i increase was more pronounced and might be the reason for the slow increase in [Mg2+]i following the initial decrease. The withdrawal of propionate or CO2/HCO3--buffered bath solutions caused a transient alkalinization which was accompanied by a slight but significant [Mg2+]i increase, even in the nominal absence of extracellular Mg2+, while [Na+]i returned to its original value. The alkalinization-induced [Mg2+]i increase could be reduced to about 50% by the application of 1-10 microM cyclosporin A, an inhibitor of the mitochondrial permeability transition pore (MTP). Phenylarsine oxide, an MTP activator, caused a [Mg2+]i increase with characteristics similar to those of the alkalinization-induced increase, which could not be attributed to any changes in [Na+]i or pHi. It is concluded that an intracellular alkalinization might induce the release of Mg2+ from intracellular stores.
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Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Sanguijuelas
/
Magnesio
/
Neuronas
Tipo de estudio:
Etiology_studies
Límite:
Animals
Idioma:
En
Revista:
Pflugers Arch
Año:
1997
Tipo del documento:
Article
País de afiliación:
Alemania