Figure 4
Effects of active linaclotide and guanylin on T84 cells: (A) Δ[cGMP] i dose response; (B) effect of 1 μM Na nitroprusside on Δ[cGMP] i ; and Effects of active linaclotide, guanylin, STa and 8BrcGMP on (C) ΔTER; (D) Δ3,000 Da FITC-dextran flux; (E) Δ70,000 Da rhodamine-dextran flux. 200 nM active linaclotide, 100 nM lubiprostone, 200 nM guanylin, 50 nM STa and 1 mM 8BrcGMP were used. Data is plotted as mean ± S.E. (A) Δ[cGMP]i dose response: EC50 lin = 15.9 ± 7.4 nM (n = 6); EC50 guan = 29.3 ± 18.4 nM (n = 6), Vmax lin = 6.5 ± 0.6 pmol/105T84 cells and Vmax guan = 9.7 ± 1.3 pmol/105 T84 cells. (B) Effect of 1 μM Na nitroprusside on Δ[cGMP]i: n = 5, *p < 0.0005 wrt lin, #p < 0.0005 wrt guan. Basal [cGMP]i = 1.55 ± 0.002 pmol/105 T84 cells. (C) ΔTER: n = 3, *p < 0.0005 wrt lubi. For lubi, lin and guan, basal DMSO TER =1.21 ± 0.02 kΩ/cm2 and basal control = 1.35 ± 0.04 kΩ/cm2; for STa and 8BrcGMP, basal control = 1.29 ± 0.02 kΩ/cm2. (D) Δ3,000 Da FITC-dextran flux: n = 3, *p < 0.0005 wrt lubi. Basal control flux = 620.9 ± 2.2 and basal DMSO flux = 902.9 ± 19.9 em units @ 518 nm. (E) Δ70,000 Da rhodamine-dextran flux: n = 3, *p < 0.0005 wrt lubi. Basal control flux = 1759.4 ± 21.8 and basal DMSO flux = 2240.7 ± 13.1 em units @ 590 nm.