Premium
The role of brain angiotensin AT2 receptors and NO in the renal sympatho‐inhibitory response to acute volume expansion in conscious rats (858.2)
Author(s) -
Abdulla Mohammed,
Johns Edward
Publication year - 2014
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.28.1_supplement.858.2
Subject(s) - losartan , endocrinology , medicine , angiotensin ii , blood pressure , saline , inhibitory postsynaptic potential , chemistry , receptor antagonist , renin–angiotensin system , antagonist , receptor
This study investigated the role of AT2 receptor and NO on the renal sympatho‐inhibitory response to volume expansion (VE). Conscious rats were subjected to VE (0.25% bwt/min saline for 10min IV) following intracerebroventricular (I.C.V.) infusion of saline, angiotensin II (Ang II) or a combination of Ang II with either losartan, PD123319 (PD), an AT2 receptor antagonist or L‐NAME, an NO synthase inhibitor. I.C.V. losartan, PD or L‐NAME did not change baseline mean arterial pressure (MAP), heart rate (HR) or renal sympathetic nerve activity (RSNA). However, I.C.V. Ang II increased MAP and decreased both HR and RSNA (113±2 vs. 107±2 mmHg, 365±7 vs. 379±5 beat/min, 1.03±0.13 vs. 1.29±0.15 µV.s, respectively, all P<0.05). VE decreased RSNA in all groups by some 27±2% (P<0.05) at the end of the 10min. Ang II, losartan or PD had no effect on the magnitude of renal sympatho‐inhibitory response to VE. However, L‐NAME decreased the sympatho‐inhibitory response compared to saline (14±3 vs. 30±5%, P<0.05). I.C.V. Ang II in combination with losartan enhanced (41±3 vs. 29±5%) but with PD decreased (15±2 vs. 28±4%, all P<0.05) the renal sympatho‐inhibition compared to Ang II. The sympatho‐inhibitory response to VE following Ang II plus L‐NAME was similar to Ang II alone. These findings suggest that activation of central AT2 receptors enhances the renal sympatho‐inhibitory response to VE but this effect is not dependent on NO. Grant Funding Source : Funded by Wellcome Trust