Membrane responses to extracellular ATP in rat isolated white adipocytes

We used whole-cell and perforated-patch voltage-clamp methods to study the membrane electrical properties of isolated rat epididymal and inguinal white adipocytes. We examined cells from both Sprague-Dawley and Zucker lean and Zucker obese (fa/fa) rats. A delayed-rectifier potassium current was pres...

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Bibliographic Details
Published in:Pflügers Archiv 1997-08, Vol.434 (4), p.422-428
Main Authors: Lee, S C, Pappone, P A
Format: Article
Language:English
Subjects:
Adenosine Triphosphate - metabolism
Adipocytes - metabolism
Animals
Cell Membrane - physiology
Cell Separation
Cells
Electric Conductivity
Electrophysiology
Extracellular Space - metabolism
Ion Channel Gating
Ion Channels - physiology
Norepinephrine - pharmacology
Obesity - genetics
Obesity - pathology
Obesity - physiopathology
Rats
Rats, Sprague-Dawley
Rats, Zucker
Reference Values
Rodents
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Summary:We used whole-cell and perforated-patch voltage-clamp methods to study the membrane electrical properties of isolated rat epididymal and inguinal white adipocytes. We examined cells from both Sprague-Dawley and Zucker lean and Zucker obese (fa/fa) rats. A delayed-rectifier potassium current was present and similar in unstimulated white fat cells from all these sources. The potassium current activated rapidly with depolarization positive to about -30 mV and showed slow inactivation. Stimulation with extracellular ATP activated both hyperpolarizing and depolarizing conductances. ATP exposure also increased cell membrane capacitance by an average of 16%, suggesting that ATP activates exocytosis. Exposure to norepinephrine had little electrophysiological effect. We conclude that white adipocytes are very similar to brown adipocytes in their resting electrophysiological profile and in their responses to extracellular ATP.
ISSN:0031-6768
1432-2013
DOI:10.1007/s004240050416