Properties of voltage-gated Ca2+ currents measured from mouse pancreatic β-cells in situ
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...
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Sociedad de Biología de Chile
2006
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oai:scielo:S0716-976020060003000122014-01-24Properties of voltage-gated Ca2+ currents measured from mouse pancreatic β-cells in situMEARS,DAVIDROJAS,EDUARDO islet of Langerhans insulin stimulus-secretion coupling ion channel inactivation kinetics BAPTA 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.info:eu-repo/semantics/openAccessSociedad de Biología de ChileBiological Research v.39 n.3 20062006-01-01text/htmlhttp://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0716-97602006000300012en10.4067/S0716-97602006000300012 |
| institution |
Scielo Chile |
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Scielo Chile |
| language |
English |
| topic |
islet of Langerhans insulin stimulus-secretion coupling ion channel inactivation kinetics BAPTA |
| spellingShingle |
islet of Langerhans insulin stimulus-secretion coupling ion channel inactivation kinetics BAPTA MEARS,DAVID ROJAS,EDUARDO Properties of voltage-gated Ca2+ currents measured from mouse pancreatic β-cells in situ |
| description |
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. |
| author |
MEARS,DAVID ROJAS,EDUARDO |
| author_facet |
MEARS,DAVID ROJAS,EDUARDO |
| author_sort |
MEARS,DAVID |
| title |
Properties of voltage-gated Ca2+ currents measured from mouse pancreatic β-cells in situ |
| title_short |
Properties of voltage-gated Ca2+ currents measured from mouse pancreatic β-cells in situ |
| title_full |
Properties of voltage-gated Ca2+ currents measured from mouse pancreatic β-cells in situ |
| title_fullStr |
Properties of voltage-gated Ca2+ currents measured from mouse pancreatic β-cells in situ |
| title_full_unstemmed |
Properties of voltage-gated Ca2+ currents measured from mouse pancreatic β-cells in situ |
| title_sort |
properties of voltage-gated ca2+ currents measured from mouse pancreatic β-cells in situ |
| publisher |
Sociedad de Biología de Chile |
| publishDate |
2006 |
| url |
http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0716-97602006000300012 |
| work_keys_str_mv |
AT mearsdavid propertiesofvoltagegatedca2currentsmeasuredfrommousepancreatic946cellsinsitu AT rojaseduardo propertiesofvoltagegatedca2currentsmeasuredfrommousepancreatic946cellsinsitu |
| _version_ |
1718441406607917056 |