Male shrs

Male SHRs (aged 3 months) were purchased from Beijing Vital River Laboratory Animal Technology Co., Ltd. The rats were housed with controlled temperature (23–25°C) and lighting (8:00 AM to 8:00 PM light, 8:00 PM to 8:00 AM dark) and with free access to food and tap water. All the animals used in this experiment received humanitarian concern. All animal experiments were approved by the Committee on ethics of biomedicine of Naval Medical University and were conducted according to the National Institutes of Health Guidelines for the Care and Use of Laboratory Animals.

Male SHRs (9 weeks old, specific pathogen free, SPF) were purchased from Vital River Laboratory Animal Technology Co., Ltd. (Beijing, China). Rats were kept under a 12 h light–dark cycle at 22 ± 4 °C with relative humidity of 50% ± 20%. The standard chow diet and distilled water were provided ad libitum during the experiments. The animals adapted to the new situation for one week before the experiment. Experimental procedures were conducted in strict accordance with the PR China legislation on the use and care of laboratory animals.
SHRs were randomly divided into 5 groups with 6 rats in each group. The heptapeptide GAAGGAF was dissolved in distilled water and SHRs were orally administrated at a dose of 7.5, 15.0 and 30.0 mg/kg BW, respectively, with distilled water and captopril as the control group served as the negative and positive control separately. All of the groups were orally administrated with the volume of 5 mL/kg body weight. The SBP of the rats were measured using the tail-cuff method [17 (link)].

Male SHRs (10 weeks, 220 ± 20 g body weight) were purchased from Vital River Laboratory Animal Technology Co., Ltd. (Beijing, China). Following an acclimation period of one week, SHRs with systolic blood pressure (SBP) higher than 180 mmHg were randomly divided into groups of ten rats. Animals were housed at 25 °C under a light–dark cycle of 12 h/12 h. TLRFALHGME was injected via tail vein at a dose of 4 mg/kg body weight.
Under the same conditions, a saline group was used as the negative control and captopril (5 mg·kg⁻¹) as the positive control. The SBP of all rats was measured using a BP-98A blood pressure monitor (Softron Biotechnology, Beijing, China) before and after intravenous administration. The rats were all treated humanely according to the guidelines of the National Institutes of Health and Use of Laboratory Animals and approved by the Ethics Committee of Guangdong Medical Laboratory Animal Center (no. 20211001, approved on 9 September 2021).

Male SHRs (10 weeks, 230 ± 20 g body weight) were purchased from Vital River Laboratory Animal Technology Co., Ltd. (Beijing, China). Following an acclimation period of one week, SHRs with systolic blood pressure (SBP) higher than 220 mmHg were randomly divided into six animals per group. Animals were housed at 25 °C under a light–dark cycle of 12 h. THDWWKER, HDWWKER, and DDQYHIF were injected via the tail vein at a dose of 12 mg/kg body weight.
Under the same conditions, a saline group was used as the model control and captopril (5 mg·kg⁻¹) as the positive control. The SBP of all rats was measured using an ALC-NIBP blood pressure monitor (Alcott Biotech, Shanghai, China) before and after intravenous administration. The rats were all treated humanely according to the guidelines of the National Institutes of Health and Use of Laboratory Animals and approved by the Ethics Committee of Guangdong Medical Laboratory Animal Center (no. 20211001, approved on 9 September 2021).

Male SHRs (n = 50) and WKY rats (n = 10, aged 4 weeks) weighing 80–100 g were purchased from Beijing Vital River Laboratory Animal Technology Co. Ltd. (Beijing, China, Permission No. SCXK (J) 2016–0001). All animals were housed in an environment with a temperature of 22 ± 1°C, relative humidity of 50 ± 1%, and a light/dark cycle of 12/12 hr. All animal studies (including the rat euthanasia procedure) were conducted in accordance with the Animal Management Rules of the Chinese Ministry of Health and with the approval of the Animal Ethics Committee of Dongzhimen Hospital affiliated with Beijing University of Chinese Medicine (No. 21–27).