Abstract
The aim of this study was to investigate the effects of increased angiotensin II type 2 receptor (AT2R) expression in the nucleus of the solitary tract (NTS) on neurogenic hypertension. Ten week old normotensive (NT) Holtzman and spontaneously hypertensive rats (SHRs) were microinjected in the NTS with either AAV2‐CBA‐AT2R or AAV2‐CBA‐eGFP (n=5‐8/group). Telemetry and baroreflex were performed on four experimental groups: NTeGFP, NTAT2R, SHReGFP and SHRAT2R. At termination brains were harvested for RT‐PCR. No significant change in mean arterial pressure (MAP) was observed in all groups from baseline to 4 weeks post viral transfection, but SHReGFP and SHRAT2R showed a significant elevation in MAP compared to NTeGFP and NTAT2R groups (138 ± 4 and 136 ± 4 vs. 94 ± 2 and 97 ± 6 mmHg, respectively). SHReGFP showed a significantly impaired baroreflex compared to NTeGFP and NTAT2R (‐0.5 ± 0.1 vs. ‐1.1 ± 0.1 and ‐1.4 ± 0.1 bpm/mmHg, respectively). SHRAT2R show significant improvement in baroreflex compared to SHReGFP (‐0.70 ± 0.1 vs. ‐0.5 ± 0.1 bpm/mmHg, respectively). SHRAT2R have significantly higher mRNA levels of MAS and angiotensin converting enzyme 2 (ACE2) compared to SHReGFP (MAS: 1.6 ± 0.1 vs. 0.7 ± 0.3 and ACE2: 8.5 ± 1.6 vs. 2.0 ± 0.4). While AT2R is ineffective at modulating chronic MAP, the baroreflex is significantly improved in SHR possibly via the MAS/ACE2 axis, suggesting a potential beneficial effect of AT2R.Grant Funding Source: Supported by: CNPq/PRONEX, FAPESP/PNDP‐CAPES, NIH HL‐076803
Published Version
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