Author/Editor		Chowdhury, Helena H; Grilc, Sonja; Zorec, Robert
Title		Correlated ATP-induced changes in membrane area and membrane conductance in single rat adipocytes
Type		članek
Source		Ann N Y Acad Sci
Vol. and No.		Letnik 1048
Publication year		2005
Volume		str. 281-6
Language		eng
Abstract		In the past few years it has been shown that, like many other nonneuroendocrine cells, adipocytes possess a mechanism for triggered exocytosis. Endocytosis and exocytosis affect the plasma membrane surface area, which can be directly monitored with electrophysiological patch-clamp techniques by measuring membrane capacitance, a parameter linearly related to the plasma membrane area. In this study we used the whole-cell mode of the patch-clamp technique to measure changes in membrane capacitance to monitor the effect of extracellular adenosine triphosphate (ATP) on the dynamics of membrane area changes in single adipocytes. Experimental evidence shows that extracellular application of ATP (100 uM) increases membrane capacitance for 30+-2 % . In controls a significantly smaller increase of 3+-2% was measured, which is due to a slow exocytic-endocytic membrane cycling rate of 0.3%/min. We found that ATP induces a transient increase in membrane current, temporally associated with the peak rate in membrane capacitance increase. These results show directly the presence of ATP-induced increase in membrane area correlated to the increase in membrane current in single adipocytes.
Descriptors		ADIPOCYTES ADENOSINE TRIPHOSPHATE MEMBRANE POTENTIALS ENDOCYTOSIS EXOCYTOSIS ELECTRIC CONDUCTIVITY PATCH-CLAMP TECHNIQUES RATS, WISTAR