Effect of high-salt (HS) diet and vildagliptin on blood pressure (BP) profile and heart rate, glucagon-like peptide 1 (GLP-1) and dipeptidyl peptidase-4 (DPP-4) in Dahl salt-sensitive (DSS) rats. Twenty-four-hour mean arterial pressure (MAP) (a) and hourly MAP at five time points per day (b) as measured by the telemetry system. Normal salt (NS) diet for 2 weeks does not alter the MAP, whereas HS diet significantly increases MAP after 7 days in DSS rats. Vildagliptin dose-dependently suppressed salt-dependent hypertension. After switching to the NS diet, MAP is reduced. Further, BP reduction is observed by NS+vildagliptin treatment. Systolic blood pressure (SBP, c), diastolic blood pressure (DBP, d) and heart rate (HR, e) in DSS rats fed a HS-diet for 7 days followed by NS diet for 7 days. The SBP and DBP of DSS rats fed a NS diet for 2 weeks do not change, whereas HS diet significantly increased the SBP and DBP after 7 days. Vildagliptin dose-dependently suppressed the BP elevation induced by HS diet. After switching to NS diet, SBP and DBP significantly decreased, and further BP reduction was observed in dietary salt reduction with vildagliptin treatment. However, HR was not significantly different between the treatment groups. Effects of vildagliptin on active plasma GLP-1 (f) and DPP-4 activity (g). The concentration of active GLP-1 in plasma is increased by high doses of vildagliptin in DSS rats. Plasma DPP-4 activity is reduced by vildagliptin in a dose-dependent manner. ***P<0.005 NS+vehicle vs. HS+vehicle; ††P<0.01, †††P<0.005 HS+vehicle vs. HS+vildagliptin-high dose; §P<0.05, §§§P<0.005 HS+vildagliptin-low dose vs. HS+vildagliptin-high dose; ∥∥∥P<0.005 vs. baseline in respective group; ###P<0.005 vs. 7 days after HS diet in respective group.