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. 2009 Mar 16;587(Pt 10):2225–2231. doi: 10.1113/jphysiol.2008.163550

Figure 4. Membrane stretch vs. cell volume changes.

Figure 4

Previous studies (B and D, see Grunnet et al. 2002, 2003) on the effect of cell volume changes performed in Xenopus oocytes expressing either KCNQ1 or BK channels showed that KCNQ1 channels are sensitive to small changes in cell volume: the relative current increased by cell swelling (70%) and decreased after cell shrinkage (40%). In contrast, cell volume changes had no significant effect on BK currents. The present study (A and C), demonstrated that the volume-sensitive KCNQ1 channels are not affected by membrane stretch, whereas the volume insensitive BK channels are highly stretch-activated; the BK current increased by 480% in response to pressure (−5.0 ± 0.3 mmHg).