What question did this study set out to answer?

To characterize the electrical burst patterns and calcium-activated potassium permeability in pancreatic islet beta-cells from ob/ob obese mice compared with normal mice.

January 22, 1985Quarterly Journal of Experimental Physiology

MEMBRANE POTENTIAL MEASUREMENTS IN ISLETS OF LANGERHANS FROM ob/ob OBESE MICE SUGGEST AN ALTERATION IN Ca2+i‐ACTIVATED K+ PERMEABILITY

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Authors

LRLuı́s M. RosárioUniversity of Coimbra IAI. AtwaterUniversity of Chile EREduardo RojasUniversity of Antofagasta

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Implication

Electrophysiological study reveals altered burst firing and drug sensitivity in islet beta-cells of ob/ob mice, indicating modified calcium-activated potassium permeability.

Key Points

To characterize the electrical burst patterns and calcium-activated potassium permeability in pancreatic islet beta-cells from ob/ob obese mice compared with normal mice.
Used high-resistance micro-electrodes to measure membrane potentials of islet beta-cells from ob/ob obese mice (Norwich colony) in modified Krebs solution across glucose concentrations up to 33 mM.
Evaluated electrical responses to the mitochondrial inhibitor carbonyl-cyanide m-chlorophenylhydrazone and potassium permeability blockers quinine and glibenclamide.
In 11 mM glucose, ob/ob beta-cells had an average active-phase duration of 20 s versus 5 s in normal beta-cells, with an average burst frequency of 1.8 bursts/min versus 3 bursts/min in normal controls.
The glucose concentration for half-maximal spike frequency shifted to 6.9 mM in ob/ob beta-cells compared to 10.2 mM in normal beta-cells, with burst firing persisting at concentrations as high as 33 mM glucose.
Carbonyl-cyanide m-chlorophenylhydrazone induced hyperpolarization, but quinine and glibenclamide failed to block the silent phase between electrical bursts in ob/ob beta-cells.

Cite This Study

Rosário et al. (1985) studied this question.

synapsesocial.com/papers/6a6fbbbe660549caf2c446b8 https://doi.org/10.1113/expphysiol.1985.sp002885

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Implication

Electrophysiological study reveals altered burst firing and drug sensitivity in islet beta-cells of ob/ob mice, indicating modified calcium-activated potassium permeability.

MEMBRANE POTENTIAL MEASUREMENTS IN ISLETS OF LANGERHANS FROM ob/ob OBESE MICE SUGGEST AN ALTERATION IN Ca2+i‐ACTIVATED K+ PERMEABILITY

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Key Points

Cite This Study

MEMBRANE POTENTIAL MEASUREMENTS IN ISLETS OF LANGERHANS FROM ob/ob OBESE MICE SUGGEST AN ALTERATION IN Ca2+i‐ACTIVATED K+ PERMEABILITY

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Cite This Study

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