Glycolytic flux in permeabilized freshly isolated vascular smooth muscle cells

To determine whether channeling of glycolytic intermediates can occur in vascular smooth muscle (VSM), we permeabilized freshly isolated VSM cells from hog carotid arteries with dextran sulfate. The dextran sulfate-treated cells did not exclude trypan blue, a dye with molecular weight of approximately 1,000. If glycolytic intermediates freely diffuse, plasmalemmal permeabilization would allow intermediates to exit the cell and glycolytic flux should cease. We incubated permeabilized and nonpermeabilized cells with 5 mM [1-13C]glucose at 37 degrees C for 3 h. 13C nuclear magnetic resonance (NMR) was used to determine relative [3-13C]lactate production and to identify any 13C-labeled glycolytic intermediates that exited from the permeabilized cells. [3-13C]lactate production from [1-13C]glucose was decreased by an average of 32% (n = 6) in permeabilized cells compared with intact cells. No 13C-labeled glycolytic intermediates were observed in the bathing solution of permeabilized cells. We conclude that channeling of glycolytic intermediates can occur in VSM cells.