Bp 2000

Adult male Sprague–Dawley rats (weight, 250–300 g; age, 7–8 weeks) were used in this study. The systemic hypotensive rat model was designed using HCTZ (Dichlozid; Yuhan, Seoul, Korea; 100 mg/kg dissolved in drinking water) to lower systemic BP without interfering with the Ang pathways [23 (link),38 (link)]. The animals were randomly assigned to either the experimental or control groups. Systolic and diastolic BP were measured using a tail cuff sphygmomanometer (Visitech BP2000, Visitech Systems, Apex, NC, USA) twice daily at the same time [39 (link),40 (link)]. Measurements were obtained every week throughout the 12-week experimental period, and the mean value of the two measurements was calculated. The time and frequency of water drinking by individual rats were irregular, which could induce BP fluctuations. Rats without a significant reduction in systolic BP < 120 mmHg or diastolic BP < 80 mmHg were excluded (7 of 104 animals; 6.7%). The standard deviations (SDs) of all measurements were calculated and the mean SD of each group was considered the BP fluctuation.

Arterial pressure was measured using a non-invasive blood pressure measurement system, i.e. a tail-cuff sphygmomanometer equipped with the photoplethysmogram Visitech BP-2000 (Visitech Systems, Apex, NC). Mice were accustomed to the procedure for 5 consecutive days before measurement and were monitored weekly during the 7 weeks of the study. For blood pressure measurements, the mice were placed in a warm (37 °C) restraint device with an appropriately sized cuff around the tail. In order to minimize stress-induced blood pressure fluctuations in the animals, all measurements were taken after a 5-min adaptation period. All measurements of diastolic and systolic pressures were taken between 9:00 a.m. and 12:00 a.m., and recordings were averaged from at least 5 consecutive readings using BP-2000 analysis software. Mean arterial pressure was calculated using following formula: [(2 × diastolic) + systolic]/3.

SBP was measured using a tail-cuff sphygmomanometer (Visitech BP2000, Visitech Systems, Apex, NC). All animals were acclimated for blood pressure measurements 1 week before drug treatment.

Anatomic parameters were obtained by 2D‐directed M‐mode echocardiography (Vevo770; Visual Sonics, Bothell, WA), functional parameters by Doppler Ultrasound (Model DSPW, Indus Instruments, Webster, TX) as described previously (Duerrschmid et al. 2013). Data were stored and analyzed offline. Blood pressure measurements were obtained by the tail‐cuff method (VisitechBP2000, Visitech Systems, Apex, NC) (Duerrschmid et al. 2013).

Body weight (BW) of the offspring was measured every month until they reached 6 months of age. Blood pressure was measured in conscious, 6-month-old rats using the indirect tail-cuff method (BP-2000; Visitech Systems, Inc., Apex, NC) [6 (link), 18 (link)].