Endogenous nitric oxide on arterial hemodynamics: a comparison between normotensive and hypertensive rats

oxide on arterial hemodynamics: a comparison between nor-motensive and hypertensive rats. Am. J. Physiol. 273 (Heart Circ. Physiol. 42): H1816–H1823, 1997.—Endogenous nitric oxide (NO) plays an important role in maintaining a vasodila-tor tone. In the present study, we compared the effects of NO blockade on the steady and pulsatile components of arterial hemodynamics between spontaneously hypertensive rats (SHR) and normotensive Wistar-Kyoto strain (WKY), 22–26 wk of age. In the first series of experiments, various doses (1–30 mg/kg iv) of NG-nitro-L-arginine methyl ester (L-NAME) were administered to block the NO release in anesthe-tized WKY and SHR. In both WKY and SHR, L-NAME caused a dose-dependent increase in arterial pressure (AP) with a decrease in heart rate (HR). The maximal effects of L-NAME on AP and HR occurred at a dose of 10 mg/kg. Both the AP increase and HR decrease were higher in SHR (AP, 138 6