Fig. 5: The activity of group 1 CCK-positive neurons in the SFO under the Na-depleted condition is attenuated by salt intake, but not fluid intake.
a Experimental protocols for Ca2+ imaging of group 1 CCK-positive neurons in the CCK-Cre mouse during 0.3 M NaCl or 0.3 M sucrose drinking under the Na-depleted condition. A large proportion of the intake of both fluids ceased within 20 min. b Raster plots of calcium responses in individual group 1 CCK-positive neurons under each sequential condition (n = 36 neurons in two mice). c Dot plot of calcium responses in individual CCK-positive neurons during 30 s at four temporal positions in (b). n = 36 neurons in two mice. ns, not significant; **P < 0.01; two-sided one-way RM ANOVA (NaCl, F(3,33) = 24.80, P = 1.38 × 10−8; sucrose F(3,33) = 33.87, P = 3.47 × 10−10), with post hoc two-sided paired Student’s t-tests (NaCl, P(ii vs iii) = 9.84 × 10−7, P(ii vs iv) = 9.21 × 10−9; sucrose, P(ii vs iii) = 0.571, P(ii vs iv) = 0.196). Box-plot elements (center line, upper and lower box limits, whiskers, and points) were defined as medians, quartiles, 1.5× interquartile ranges, and outliers. d Changes in calcium responses from those under the Na-depleted condition. **P < 0.01; two-sided paired Student’s t-tests (P(iii) = 3.47 × 10−8; P(iv) = 3.24 × 10−8). e Left: Injection of AAV-DIO-mCherry into the SFO of the CCK-Cre mouse. Right: Experimental protocol for the induction of the Na-depleted condition. f Immunohistochemical staining of mCherry and Fos in the SFO under the control and Na-depleted conditions. Arrowheads indicate double-positive cells under the Na-depleted condition. These images were reproduced from more than three independent mice. Scale bar, 50 µm. g Ratio of Fos-positive cells to mCherry-positive cells in the SFO (n = 8 sections each). **P < 0.01, two-sided Mann–Whitney U tests (U = 0, P = 2.97 × 10−4). Data represent the mean ± s.e.m. in (d) and (g).
