Inhibition of glucose-induced electrical activity in rat pancreatic beta-cells by DCPIB, a selective inhibitor of volume-sensitive anion currents.
Eur J Pharmacol
; 489(1-2): 13-9, 2004 Apr 05.
Article
en En
| MEDLINE
| ID: mdl-15063150
We have investigated the effects of the ethacrynic acid derivative 4-(2-butyl-6,7-dichloro-2-cyclopentyl-indan-1-on-5-yl) oxobutyric acid (DCPIB), an inhibitor of the volume-sensitive anion channel (VSAC), on electrical activity and insulin secretion in rat pancreatic beta-cells. DCPIB inhibited whole-cell VSAC currents in beta-cells with IC50 values of 2.2 and 1.7 microM for inhibition of outward and inward currents, respectively. DCPIB also inhibited the VSAC at the single channel level in cells activated by glucose. In intact cells, DCPIB caused a net increase in beta-cell input conductance and evoked an outward current that was sensitive to inhibition by tolbutamide, suggesting KATP channel activation. However, no KATP channel activation was evident under conventional whole-cell conditions, suggesting that the drug might activate the channel in intact cells via an indirect mechanism, possibly involving nutrient metabolism. DCPIB suppressed glucose-induced electrical activity in beta-cells, hyperpolarised the cell membrane potential at a substimulatory glucose concentration and prevented depolarisation when the glucose concentration was raised to stimulatory levels. The suppression of electrical activity by DCPIB was associated with a marked inhibition of glucose-stimulated insulin release from intact islets. It is concluded that DCPIB inhibits electrical and secretory activity in the beta-cell as a combined result of a reciprocal inhibition of VSAC and activation of KATP channel activities, thus producing a marked hyperpolarisation of the beta-cell membrane potential.
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Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Islotes Pancreáticos
/
Ciclopentanos
/
Glucosa
/
Indanos
/
Canales Iónicos
Tipo de estudio:
Diagnostic_studies
Límite:
Animals
Idioma:
En
Revista:
Eur J Pharmacol
Año:
2004
Tipo del documento:
Article
Pais de publicación:
Países Bajos