Figure 2.

Effects of 5-HT on basal fluid secretion in interlobular duct segments isolated from guinea pig pancreas. The closed ducts were initially superfused with HCO₃^–-CO₂-free HEPES-buffered solution. After a 5-minute period, the bath solution was switched to the standard HCO₃^–-CO₂–buffered solution. After a further 10 minutes, 0.1 μM 5-HT was added to the bath in the presence of HCO₃^–-CO₂. The fluid secretory rates are shown as means ± SEM of four experiments.