Anxiety-like behavior shown by using an open-field test in adult and old rats fed normal- or high-salt diets for 4 wk. The open-field test determined percentage of time spent in the center of the open-field arena (A), total activity (B), distance traveled (C), ambulatory activity (D), rearing (E), and fecal boli (F) for 15 min using Opto-varimax software. Bars are means ± SEMs, n = 10. Means without a common letter differ, P < 0.05. A-HS, adult, high-salt diet; A-NS, adult, normal-salt diet; O-HS, old, high-salt diet; O-NS, old, normal-salt diet.