Effects of K+, pH and glutamate on 45Ca kinetics in hippocampal brain slices.
J Neurosci Methods
; 59(1): 111-20, 1995 Jun.
Article
em En
| MEDLINE
| ID: mdl-7475241
ABSTRACT
Altered calcium homeostasis is likely to play a pathogenetic role in cerebral ischemia. In order to further understand which factors associated with ischemia contribute to disturbances of calcium metabolism, the influence of 3 isolated insults, 8 mM K+, pH 6.1 and 1 mM glutamate, on total tissue calcium were studied by analysis of steady-state kinetics of 45Ca in 500 microns hippocampal brain slices. 45Ca kinetics were analyzed with 2 bi-exponential models by non-linear least-squares analysis. Tissue wet weight/protein was measured simultaneously. Each experimental condition produced a unique tissue response. Raising K+ had no effect on tissue water but increased the rate of uptake of Ca2+ into the larger, rapidly equilibrating tissue Ca2+ space. Acidosis reduced tissue water and the amount of Ca2+ in the slowly equilibrating compartment due to enhanced efflux from that space. Glutamate increased tissue water in a time-dependent manner and increased the influx and amount of Ca2+ in the slowly equilibrating space. Combined insults revealed minimal interaction between K+ and acidosis or glutamate, but glutamate with acidosis worsened tissue injury. We discuss the relationship of this technique to other methods for studying tissue calcium and the significance of the observations regarding ischemia.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Radioisótopos de Cálcio
/
Compostos de Potássio
/
Ácido Glutâmico
/
Hipocampo
/
Concentração de Íons de Hidrogênio
Tipo de estudo:
Prognostic_studies
Limite:
Animals
Idioma:
En
Revista:
J Neurosci Methods
Ano de publicação:
1995
Tipo de documento:
Article
País de afiliação:
Estados Unidos