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Interaction between α 1B adrenoceptors and AT 1 receptors in the control of renal haemodynamics in Sprague Dawley (SD) rats with pressure over load induced left ventricular hypertrophy
Author(s) -
Rathore Hassaan Anwer,
AbdulSattar Munavvar Zubaid,
Abdullah NoorAzizan,
Johns Edward J
Publication year - 2009
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.23.1_supplement.804.8
Subject(s) - methoxamine , phenylephrine , medicine , endocrinology , blood pressure , hemodynamics , pressure overload , muscle hypertrophy , perfusion , receptor , mean arterial pressure , left ventricular hypertrophy , chemistry , agonist , heart rate , cardiac hypertrophy
This study examined the interaction between α 1B adrenoceptors and AT 1 receptors in the control of renal hemodynamics in rats with pressure overload ventricular hypertrophy. Groups (n=6 each) of male SD rats were subjected to sham surgery (controls) or supra renal aortic banding (AB). On day 45, rats were anaesthetized and prepared for measurement of mean arterial pressure (MAP) and renal cortical blood perfusion (CBP). The changes in CBP caused by intra renal administration of noradrenaline, phenylephrine, methoxamine and ANGII were determined before and after blocking renal α 1B adrenoceptors using chlorethylclonidine (CEC). Data, means ± SEM were subjected to ANOVA with significance at P <0.05. Baseline MAP was higher in the AB group, 142±3 vs 105±2 mmHg, but CBP was lower, 624±28 vs 838±21 BPU (both P <0.05), than the control group. The low dose of CEC enhanced the vasoconstrictor responses to methoxamine in the AB group by 10% ( P <0.05) compared to the vehicle phase. The high dose of CEC decreased the vasoconstrictor responses to all adrenergic agonists by 10‐20% in the control group versus 30‐60% in the AB group (all P <0.05) and to ANGII by 10% in the control and by 5% in AB group (both P <0.05). These data showed an increased functional importance of renal α 1B adrenoceptors in pressure overload hypertrophy through a possible cross talk mechanism with renal AT 1 receptors.