Figure 2 | Scientific Reports

Figure 2

From: Hormonal regulation of thirst in the amphibious ray-finned fish suggests the requirement for terrestrialization during evolution

Figure 2

Amphibious behaviour in mudskippers after intracerebroventricular (ICV) injection of ANP in the presence of angiotensin II (AngII). (a,b) Schematic diagram of experimental tank used to observe amphibious behaviour of mudskippers. Top (a) and side (b) views. 10-ppt seawater is close to their natural environment and almost identical to the salinity of body fluids, and thus was chosen for the experiments. (c,d) Timecourse changes in amphibious behaviour. The frequency of migration (c) and the period of time in water (d) were measured after ICV injection with 0.1 μl/g of 3 × 10−8 M AngII alone (n = 6, open diamonds), 3 × 10−8 M (n = 4, red triangles) to 3 × 10−7 M ANP (n = 7, red circles) in the presence of AngII, and vehicle (n = 8, open circles). The parameters were measured at 0.5 h (0.25–0.75 h), 1 h (0.75–1.25 h), 2 h (1.75–2.25 h), 4 h (3.75–4.25 h) and 8 h (7.75–8.25 h) after injections. No apparent sex differences were found in these effects. Three-way ANOVA (with time course, hormones, and doses) and Tukey’s post-hoc test were used for statistical analysis. Data are shown as means ± standard error of the mean (s.e.m.). *p = 0.012, p = 0.009, ††p = 0.0022.

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