Fig. S1.

One hundred micromolar amiloride disrupts overnight intake of 0.45 M NaCl in sodium-depleted rats (related to Fig. 1). Previous work indicates that amiloride, an epithelial sodium channel blocker, disrupts consumption of hypertonic NaCl solutions by sodium-deficient rats (SI Experimental Procedures). We confirmed this result for 0.45 M NaCl by inducing sodium appetite in rats (n = 12) on two separate days spaced 1 wk apart. Following 24-h sodium depletion, rats were given ad libitum home cage access to either 0.45 M NaCl alone or 0.45 M NaCl mixed with 100 μM amiloride in a counterbalanced fashion. Deplete rats consumed significantly less 0.45 M NaCl in the presence of 100 μM amiloride compared with 0.45 M NaCl alone (W = 66, **P < 0.01; Wilcoxon matched pairs test). Thus, even at NaCl concentrations as high as 0.45 M, 100 μM amiloride is sufficient to disrupt the ability of sodium-depleted rats to identify and exploit sources of sodium.