Fig. 5
From: A sodium binding system alleviates acute salt stress during seawater acclimation in eels
Bound Na, Cl, and Os in eel tissues. a Bound Na distribution in a blood vessel (BV) of eel after 1 d in SW. The Na-scan is overlaid on the scanning electron micrograph. The blood vessel lumen is filled with blood cells (BC) with low bound Na in the plasma space, indicating that the fixation process has removed Na from the aqueous space, leaving only bound Na in the tissue. Scale bar = 100 μm. b Comparison between bound Na and Cl distribution in the middle intestine and skin after 3 h and 1 d in SW respectively, showing that their distribution are not paralleled. In scale (Sc), bound Na was high while Cl was almost undetectable. The bound Na was higher than the bound Cl in the mucus secretion and desquamated cell mass (while arrow). c Comparison between Na and Os distribution in esophagus (Eso) after 3 h and 1 d in SW respectively. The distribution of bound Na and Os were not paralleled. Bound Na was high in mucus cells (white arrows), mucus secretion, and desquamated cell mass with average bound Os. d Goblet cells (yellow arrows) and club cells (white arrows) are present on the secretory epithelium of eel esophagus and both cell types contain bound Na. Lu = lumen; Mu = muscle; Pa = pancreas. Lu = lumen; Ep = epidermis; De = dermis; Hy = hypodermis; Mu = muscle