Hypertension
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We studied the total vascular pressure-volume relationship and cardiac output (CO) in conscious rats receiving DOCA-salt or sham treatment. The mean circulatory filling pressure (MCFP) was measured by briefly inflation an indwelling balloon in the right atrium, and the MCFP-blood volume (BV) relationship over +/- 10% of BV was determined by rapid blood infusion or withdrawal. CO was measured in separate experiments using Fick's principle. ⋯ Arterial compliance decreased at 5 and 8 weeks. CO remained unaltered at 1, 2, 5, and 8 weeks. These results suggest that the altered total vascular capacity may serve to maintain a normal CO against a rising afterload in the conscious DOCA-salt hypertensive rats, and that the decreased total vascular capacity may be a secondary hemodynamic feature with progression of hypertension.