Figure 2: Myocardial contractility and diastolic function after 30-min hyperosmotic perfusion. Hyperosmotic NaCl perfusion (osmolarity at 320, 350 and 400 mOsm/L versus control at 300 mOsm/L) enhanced myocardial contractility (a) in both normotensive Wistar-Kyoto rats (WKY) and stroke-prone spontaneously hypertensive rats (SHRSP). Diastolic dysfunction in SHRSP was significantly ameliorated by hyperosmotic NaCl (b, c). Hyperosmotic perfusion was also effective in reducing heart rate and workload in SHRSP at higher osmolarity (d, e). LVEDP, left ventricular end-diastolic pressure; RPP, rate-pressure product. n=9-10. *P<0.05, **P<0.01 versus respective controls.