Tail cuff plethysmography

Systolic blood pressure was recorded using tail-cuff plethysmography (Columbus Instruments). Briefly, 3- to 4-month-old mice were trained for 1 week (twice daily) before recording baseline systolic blood pressure for two consecutive days. For implanting osmotic minipumps, mice were anesthetized with 5% isoflurane and maintained with 2% isoflurane inhalation in 100% O₂. Osmotic minipumps (ALZET 2004; Durect Corp.) containing Ang II (Bachem) were implanted subcutaneously as previously described (49 (link)). The Ang II infusion rate was 1.4 mg/kg per day. After recovery from anesthesia, mice were housed in individual cages and allowed free access to food and water. Systolic blood pressure recordings were continued on days 4, 7, 10, 14, 18, and 21 after minipump implantation. The systolic blood pressures in mice infused with 0.9% saline for 3 weeks (120.9 ± 4.6 mmHg, n = 4 mice) were not different from those of normal C57BL6/J mice. CCh (1 µM)–induced dilations in mesenteric arteries from saline-infused mice (79.1 ± 4.5% of maximum, n = 4) were also not different from those of normal C57BL6/J mice. Therefore, uninfused C57BL6/J mice were used as a control group for subsequent experiments.