QUICK SEARCH:   [advanced] Author: Keyword(s):
Home     Help     Feedback     Subscriptions     Archive     Search     Table of Contents

Help viewing high resolution images Return to article

Fig. 2. Volume changes of Retzius neurons under anisotonic conditions. Volume changes were measured via the fluorescence intensity of Fura-2 excited at its isosbestic wavelength (see text for details). (A) Hypertonic solution (+85 mmol l^–1 NaCl, 0.5 ₀/_exp) induced cell shrinkage. In 24 out of a total of 84 cells regulatory volume increase (RVI) was observed, during which the cell volume partly recovered from a minimum of 77±7% of the control value in standard leech saline (SLS) to 82±6%. (B) Raising the extracellular osmolality caused decreases in the cell volume that were significantly smaller than expected for an ideal osmometer (broken line). Note that the cell shrinkage was not dependent on whether the extracellular osmolality was increased by adding NaCl, which also raises the osmotic strength of the extracellular solution, or by adding carbohydrates such as sorbitol or glucose, which leaves the ionic strength constant. (C) Hypotonic solution (–59 mmol l^–1 NaCl, 2.4 ₀/_exp) induced cell swelling. A regulatory volume decrease (RVD) was never observed (N=75, –40 to –81 mmol l^–1 NaCl). (D) Reducing the extracellular osmolality caused cell volume increases that were significantly smaller than expected for an ideal osmometer (broken line). Vol_rel, relative cell volume. V₀ and V_exp, cell volume at osmolality ₀ and _exp, with index `0' indicating isotonic conditions (SLS) and index `exp' indicating experimentally changed, anisotonic conditions. The volume of an ideal osmometer is inversely proportional to the osmolality of the surrounding medium. This relationship is indicated by the broken line in B and D. Data in B and D are means ± s.d. of N=2–84 experiments.

Return to article