Excess membrane cholesterol alters human gallbladder muscle contractility and membrane fluidity  Qian Chen*, Joseph Amaral‡, Piero Biancani*, Jose Behar*  Gastroenterology  Volume 116, Issue 3, Pages 678-685 (March 1999) DOI: 10.1016/S0016-5085(99)70190-3 Copyright © 1999 American Gastroenterological Association Terms and Conditions

Fig. 1 Schematic representation of the lipid-soluble probe TMA-DPH in plasma membranes of gallbladder muscle. The probe was excited with vertically polarized light (390-nm wavelength), and emission intensity (450-nm wavelength) was measured parallel (Ivv) and perpendicular (Ivh) to the vertical plane of polarization of the excitation light. Anisotropy value (γ) was calculated from this equation. Ivv and Ivh represent vertical and horizontal intensity of the emitted light-passing polarizers. G is a grating correction factor. Gastroenterology 1999 116, 678-685DOI: (10.1016/S0016-5085(99)70190-3) Copyright © 1999 American Gastroenterological Association Terms and Conditions

Fig. 2 Maximally effective dose of CCK-8 (10 nmol/L)-induced contraction of gallbladder muscle cells from patients with cholesterol and pigment stones. Values are expressed as means ± SE of 4 experiments. *P < 0.01, Student t test. Gastroenterology 1999 116, 678-685DOI: (10.1016/S0016-5085(99)70190-3) Copyright © 1999 American Gastroenterological Association Terms and Conditions

Fig. 3 Cholesterol (Ch), phospholipid (Pl) contents, and cholesterol/phospholipid mole ratio (Ch/Pl) in purified plasma membranes of gallbladders with cholesterol stones (2) and pigment stones (■). Values are expressed as means ± SE of 4 experiments. *P < 0.05, Student t test. Gastroenterology 1999 116, 678-685DOI: (10.1016/S0016-5085(99)70190-3) Copyright © 1999 American Gastroenterological Association Terms and Conditions

Fig. 4 Steady-state fluorescence anisotropy of TMA-DPH in plasma membranes of gallbladders with cholesterol and pigment stones. Fluorescence polarization was measured by spectrofluorometer equipped with polarizers under optimal excitation wavelength of 390 nm and emission wavelength of 450 nm at 25°C. Anisotropy (γ), the reciprocal of membrane fluidity, was calculated by using the Perrin equation.24 Values are expressed as means ± SE of 3 experiments. *P < 0.05, Student t test. Gastroenterology 1999 116, 678-685DOI: (10.1016/S0016-5085(99)70190-3) Copyright © 1999 American Gastroenterological Association Terms and Conditions

Fig. 5 Maximally effective dose of CCK-8 (10 nmol/L)-induced contraction of gallbladder muscle cells from patients with cholesterol stones after incubation with cholesterol-free liposomes (2) or HEPES buffer (■) for 2 or 4 hours. Cell contraction is expressed as the percent shortening of untreated cell length. Values are expressed as means ± SE of 3 experiments. *P < 0.05 compared with incubation with HEPES alone, by Student t test. Gastroenterology 1999 116, 678-685DOI: (10.1016/S0016-5085(99)70190-3) Copyright © 1999 American Gastroenterological Association Terms and Conditions

Fig. 6 Cholesterol (Ch), phospholipid (Pl) contents, and cholesterol/phospholipid mole ratio (Ch/Pl) in purified plasma membranes of gallbladders with cholesterol stones after incubation with cholesterol-free liposomes (■) or HEPES buffer (2) for 4 hours. Values are expressed as means ± SE of 3 experiments. *P < 0.05 compared with incubation with HEPES alone, by Student t test. Gastroenterology 1999 116, 678-685DOI: (10.1016/S0016-5085(99)70190-3) Copyright © 1999 American Gastroenterological Association Terms and Conditions

Fig. 7 Fluorescence anisotropy (γ) of TMA-DPH in plasma membranes of gallbladders with cholesterol stones after incubation with cholesterol-free liposomes or HEPES buffer for 4 hours. Values are expressed as means ± SE of 3 experiments. *P < 0.05 compared with incubation with HEPES alone, by Student t test. Gastroenterology 1999 116, 678-685DOI: (10.1016/S0016-5085(99)70190-3) Copyright © 1999 American Gastroenterological Association Terms and Conditions