Figure 4. Hyposmotic swelling does not cause translocation of Cav 1 or Cav 3 from caveolar membrane fractions.

Ventricular myocytes were exposed to isotonic or hypotonic solutions for 15 min, then subject to Na₂CO₃ extraction and discontinuous sucrose density gradient fractionation. A. Mean data showing Cav 1 in each fraction normalised to the sum of Cav 1 in all fractions for each sample (n = 6 hearts). Representative immunoblots, with equal volume loading of fractions, is shown below. B. Mean data showing Cav 3 in each fraction with representative immunoblots below. In both isotonic and hypotonic conditions, Cav 1 and 3 were enriched in the buoyant lipid raft fractions (5,6) of the myocyte. Hyposmotic swelling had no effect on the location of either Cav isoform.