| Registro completo |
| Provedor de dados: |
Biol. Res.
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| País: |
Chile
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| Título: |
Properties of voltage-gated Ca2+ currents measured from mouse pancreatic β-cells in situ
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| Autores: |
MEARS,DAVID
ROJAS,EDUARDO
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| Data: |
2006-01-01
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| Ano: |
2006
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| Palavras-chave: |
Islet of Langerhans
Insulin
Stimulus-secretion coupling
Ion channel
Inactivation kinetics
BAPTA
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| Resumo: |
We used the single-microelectrode voltage-clamp technique to record ionic currents from pancreatic β-cells within intact mouse islets of Langerhans at 37C, the typical preparation for studies of glucose-induced "bursting" electrical activity. Cells were impaled with intracellular microelectrodes, and voltage pulses were applied in the presence of tetraethylammonium. Under these conditions, a voltage-dependent Ca2+ current (I Cav), containing L-type and non-L-type components, was observed. The current measured in situ was larger than that measured in single cells with whole-cell patch clamping, particularly at membrane potentials corresponding to the action potentials of β-cell electrical activity. The temperature dependence of I Cav was not sufficient to account for the difference in size of the currents recorded with the two methods. During prolonged pulses, the voltage-dependent Ca2+ current measured in situ displayed both rapid and slow components of inactivation. The rapid component was Ca2+-dependent and was inhibited by the membrane-permeable Ca2+ chelator, BAPTA-AM. The effect of BAPTA-AM on β-cell electrical activity then demonstrated that Ca2+-dependent inactivation of I Cav contributes to action potential repolarization and to control of burst frequency. Our results demonstrate the utility of voltage clamping β-cells in situ for determining the roles of ion channels in electrical activity and insulin secretion.
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| Tipo: |
Journal article
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| Idioma: |
Inglês
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| Identificador: |
http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0716-97602006000300012
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| Editor: |
Sociedad de Biología de Chile
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| Formato: |
text/html
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| Fonte: |
Biological Research v.39 n.3 2006
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