Comparison of arterial blood pressure in different strains of mice.

The present study was performed to compare the resting level of arterial blood pressure when monitored for 24 h/day in outbred Swiss Webster (SW) and inbred C57BL/ 6J, A/J, C3HeB/FeJ, and SWR/J mice. Mean arterial pressure (MAP) and heart rate (HR) varied throughout the day, with maximal values observed in the hours of darkness. Systolic (SAP), MAP, and diastolic (DAP) arterial blood pressure averaged 122 +/- 2, 112 +/- 2, and 102 +/- 2 mm Hg, respectively, in conscious SW mice (N = 6). No differences were detected in the 24-h averages of MAP between SW, C57BL/6J (N = 7), A/J (N = 5), C3HeB/FeJ (N = 5), or SWR/J (N = 7) mice maintained on a normal sodium diet. Average daily heart rate (HR) was highest in the C3HeB/FeJ (665 +/- 15 beats/min) and lowest in the C57BL/6J (594 +/- 9 beats/min). The MAP was significantly increased in SW mice administered L-NAME (133 +/- 2 mm Hg, N = 5) and significantly decreased in SW mice administered captopril (99 +/- 2 mm Hg, N = 5). These studies demonstrate similar levels of resting arterial pressure in different mouse strains under baseline conditions.