AJP - Cell Physiology, Vol 262, Issue 4 C956-C962, Copyright © 1992 by American Physiological Society
Changes in cyclic strain increase inositol trisphosphate and diacylglycerol in endothelial cells
O. R. Rosales and B. E. Sumpio
Department of Cardiovascular Medicine, Yale University School of Medicine, New Haven, Connecticut 06510.
The purpose of this study was to assess the effect of cyclic strain on
phosphatidylinositol turnover in cultured bovine aortic endothelial cells
(EC). Confluent EC grown on flexible membrane bottoms were deformed by
vacuum to 24% maximum strain and subjected to two cyclic strain regimens.
In the first set of experiments, EC were subjected to deformation at a
frequency of 60 cycles/min for either 0 (stationary control), 1, 5, 10, 25,
50, or 100 cycles of stretch. In the second set of experiments, EC were
preconditioned by deforming the membranes at 60 cycles/min for 24 h. The
cycling frequency was then acutely increased to 100 cycles/min for 0, 1, 5,
10, 25, or 100 cycles. Inositol phosphate and diacylglycerol concentrations
were determined at the end of each regimen. The results demonstrate that
either the initiation of pulsatile stretch or an acute change in cyclic
stretch frequency stimulates a sequential and transient generation of
inositol trisphosphate, its metabolites inositol biphosphate and
monophosphate, and diacylglycerol. Thus EC may respond to the initiation
and change in cyclic stretch frequency by a signal transduction pathway
involving inositol lipid metabolism.
