Rapid Communication Diurnal Blood Pressure Variation and Dietary Salt in Spontaneously Hypertensive Rats

Abstract We have previously reported that high dietary salt exposure significantly increases daytime mean arterial pres-sure in spontaneously hypertensive rats (SHR) but not in normotensive Wistar-Kyoto (WKY) controls. In the present study, we used a telemetry monitoring system to evaluate the effects of high dietary salt exposure on diurnal variation of mean arterial pressure and heart rate in SHR and WKY rats. After implantation of a radio frequency transducer, SHR and WKY rats were maintained on either high (8%) or basal (1%) salt diets. Hemodynamic values were then analyzed for diurnal variation with the use of a nonlinear data-fitting program. After 2 weeks of dietary exposure, high salt-fed SHR had significantly greater 24-hour mean arterial pressure (156±3 mm Hg) than SHR receiving basal (135±2 mm Hg) and WKY rats receiving high (100±2 mm Hg) or basal (100±l mm Hg