Premium
Over expression of angiotensin type 2 receptors (AT2R) in the nucleus of the solitary tract (NTS) decreases blood pressure in normotensive rats
Author(s) -
Blanch Graziela T,
FreiriaOliveira Andre H,
Speth Robert,
Li Hongwei,
Colombari Eduardo,
Colombari Debora S,
Sumners Colin
Publication year - 2011
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.25.1_supplement.844.2
Baseline mean arterial pressure (MAP) values in AT2R knockout mice are significantly higher than in wild type animals (Gross et al. J. Hypertension 18: 955, 2000). Preliminary data from our laboratory indicated that AT2R over expression in the rostroventrolateral medulla of hypertensive rats decreases MAP. Since the NTS has an important role in the normal maintenance of MAP, the aim of this study was to test the effects of AT2R over expression in the NTS on MAP and heart rate (HR) in normotensive rats. Sprague‐Dawley male rats (200 g, n = 5 per group) were implanted with telemetry transducers into the abdominal aorta and 10 days later were microinjected into the NTS (200 nl/site, 5 sites) with either AAV2‐CBA‐AT2R (1 × 10 8 gc) or AAV2‐CBA‐eGFP (1 × 10 9 gc) for the respective over expression of AT2R (confirmed by receptor autoradiography) or GFP. Prior to viral transduction MAP was similar between all groups during light (GFP, 93±1 and AT2R, 92±1 mmHg) and dark periods (GFP, 98±1 and AT2R, 101±2 mmHg). Twenty one days after the microinjections, there was a significant decrease in MAP in the AT2R‐transduced rats in both light and dark periods (85±2 and 90±1 mmHg, respectively) compared to GFP‐transduced rats (92±2 and 100±2 mmHg, p<0.05) and to pre‐transduction values. No significant changes in HR were observed between the groups. These results suggest an important role of AT2R in the NTS for normal maintenance of MAP. Supported by: PROPe, CNPq, NIH Grant HL 076803 and American Radiolabeled Chemicals.