Water and salt permeability of gastric vesicles

摘要: Volume-dependent changes in light scatter have been shown to be a linear function of the osmotic gradient imposed upon gastric vesicles purified from hog mucosa. Observation scattered 90° incident, using Durrum stop flow system D-110, indicates that exposed hypertonic medium undergo rapid shrinkage due water loss vesicle interior. The rate constant for this movement is 1.1±0.09 sec−1 (n=10) and linearly dependent on temperature between 16 36°C. activation energy 13.93±0.60 kcal mole−1 (n=3), calculated an Arrhenius plot, inconsistent with facilitated by large-pore aqueous channel. A slower reswell phase, solute entry into intravesicular space, follows water-dependent shrink phase. KCl entry, studied because requirement active K+/H+ transport, exhibits two stages. faster, described single exponential constantly sloping background, has 7.75±0.48×10−3 (n=15). which typically accounts 90% process, demonstrates 1.94±0.23×10−4 In presence valinomycin or nigericin, fast constants one slow swelling are observed. faster phase increased (n=15) 15.74±3.7×10−3 (n=5) 17.23±3.4×10−3 (n=3) addition nigericin (1 μg ml−1) (4.5 μm), respectively. second part approximately seen control population. Transport-dependent volume significant magnitude can demonstrated following ATP equilibrated 150mm KCl. change HCl leak abolished ionophores eliminate transport-dependent pH gradient. So 4 −- substitution, eliminates overshoot phenomena observed medium, also resulting addition.