Response of TRPV1 to osmotic stimuli.
(A) Representative single cell traces of the fluorescence ratio during the perfusion of various solutions differing in osmolality at 36°C. The line on the top indicates the timing of the change from 300 mOsm (gray) to the respective osmolality (black). (B) Summary of the change in the fluorescence ratio. Data are differences between fluorescence ratios 2 min before and 4 min after the change of the solution. Osmolality-dependent changes in the [Ca2+]i were observed in HEK293-TRPV1 cells (filled circles), but not in HEK293 cells (open circles). Values are the mean ± SEM; when the SEM value was less than 0.04, the error bar is hidden behind the symbol. HEK293-TRPV1: n = 105 (250 mOsm), n = 110 (300 mOsm), n = 129 (330 mOsm), n = 109 (340 mOsm), n = 249 (350 mOsm). HEK293: n = 112 (250 mOsm), n = 121 (300 mOsm), n = 109 (350 mOsm).