FIGURE 11.

Extracellular hypotonicity induces behavioral mechanical hypersensitivity. A, mechanical withdrawal thresholds measured in rat hind paws using the von Frey test before and following hind paw injection of 100 μl of the following solutions: an isotonic saline solution (0. 9%, 310 mosm, squares, n = 8); a hypotonic saline solution (0.45%, 155 mosm, circles, n = 8); a hypotonic saline solution (155 mosm) containing 1 mm cytochalasin D (triangles, n = 8); and a hypotonic saline solution (155 mosm) containing 0.3 mm Gd³⁺ (reversed triangles, n = 8). B, mechanical withdrawal thresholds measured in rat hind paws using the von Frey test before and following hind paw injection of 100 μl of the following solutions: an isotonic saline solution (squares, n = 7); a 0.5% DMSO in saline (circles, n = 9); 1 mm CD in 0.5% DMSO saline (CD, triangles, n = 9); 0.3 mm Gd³⁺ in saline solution (Gd³⁺, reversed triangles, n = 9). BL, baseline measured before the injections. An arrow indicates the time when the solutions are injected into the hind paws. Data represent mean ± S.E., *, p < 0.05; **, p < 0.01.