ABSTRACT
The cardiovascular responses to an infusion of KRN2391, a potassium channel opener, was studied in halothane-anesthetized dogs. Intravenous administration of KRN2391 at 1.0 and 5.0 µg·kg-1·min-1 for 60 min produced dose-dependent decreases in mean arterial pressure (MAP) and systemic vascular resistance (SVR) associated with dose-dependent increases in the cardiac index (CI) and stroke volume index (SVI) but was not accompanied by an increase in heart rate (HR). The maximum decrease in MAP during the infusion of KRN2391 at 1.0 and 5.0 µg·kg-1·min-1 was -13±7% (P<0.01) and -37±10% (P<0.01), respectively. The maximum reduction in SVR after 1.0 and 5.0 µg·kg-1·min-1 was -20±11% (P<0.01) and -60±16% (P<0.01), respectively. A KRN2391 infusion of 1.0 and 5.0 µg·kg-1·min-1 increased Cl a maximum of 11±13% (P<0.05) and 65±33% (P<0.01), respectively. KRN2391 1.0 µg·kg-1·min-1 showed a tendency to increase SVI but this change was not significant, KRN2391 5.0 µg·kg-1·min-1, however, produced a significant increase in SVI. The present results demonstrate that the decrease in MAP and the increases in CI and SVI caused by KRN2391 are due to a reduction in the afterload. Therefore, we conclude that these cardiovascular profiles of KRN2391 may be benificial in perioperative uses including the control of systemic blood pressure and the treatment of hypertension during halothane anesthesia in clinical practice.
