The contributions of muscarinic receptors and changes in plasma aldosterone levels to the anti-hypertensive effect of Tulbaghia violacea

BMC Complementary and Alternative Medicine

Research Article

Ismaila Raji¹  Pierre Mugabo²  Kenechukwu Obikeze² 

[1] Faculty of Medicine, National University of Science and Technology, P.O. Box AC 939, Ascot, Bulawayo, Zimbabwe;School of Pharmacy, University of the Western Cape, Private Bag X17, 7535, Cape Town, South Africa;

关键词: Tulbaghia violacea;    Spontaneously hypertensive rats;    Blood pressure;    Heart rate;    Muscarinic receptors;    Aldosterone;   

DOI  :  10.1186/1472-6882-13-13

 received in 2012-07-19, accepted in 2012-11-12,  发布年份 2013

来源: Springer

【 摘 要 】

BackgroundTulbaghia violacea Harv. (Alliaceae) is used to treat various ailments, including hypertension (HTN) in South Africa. This study aims to evaluate the contributions of muscarinic receptors and changes in plasma aldosterone levels to its anti-hypertensive effect.MethodsIn the acute experiments, methanol leaf extracts (MLE) of T. violacea (30–120 mg/kg), muscarine (0.16 -10 μg/kg), and atropine (0.02 - 20.48 mg/kg), and/or the vehicle (dimethylsulfoxide (DMSO) and normal saline (NS)) were respectively and randomly administered intravenously in a group of spontaneously hypertensive (SHR) weighing 300 to 350 g and aged less than 5 months. Subsequently, T. violacea (60 mg/kg) or muscarine (2.5 μg/kg) was infused into eight SHRs, 20 min after atropine (5.12 mg/kg) pre-treatment. In the chronic (21 days) experiments, the SHRs were randomly divided into three groups, and given the vehicle (0.2 ml/day of DMSO and NS), T. violacea (60 mg/kg/day) and captopril (10 mg/kg/day) respectively into the peritoneum, to investigate their effects on blood pressure (BP), heart rate (HR), and plasma aldosterone levels. Systolic BP and HR were measured using tail-cuff plethysmography during the intervention. BP and HR were measured via a pressure transducer connecting the femoral artery and the Powerlab at the end of each intervention in the acute experiment; and on day 22 in the chronic experiment.ResultsIn the acute experiments, T. violacea, muscarine, and atropine significantly (p < 0.05) reduced BP dose-dependently. T. violacea and muscarine produced dose-dependent decreases in HR, while the effect of atropine on HR varied. After atropine pre-treatment, dose-dependent increases in BP and HR were observed with T. violacea; while the BP and HR effects of muscarine were nullified. In the chronic experiments, the T. violacea-treated and captropril-treated groups had signicantly lower levels of aldosterone in plasma when compared to vehicle-treated group. Compared to the vehicle-treated group, significant reduction in BP was only seen in the captopril-treated group; while no difference in HR was observed among the groups.ConclusionThe results obtained in this study suggest that stimulation of the muscarinic receptors and a reduction in plasma aldosterone levels contribute to the anti-hypertesive effect of T. violacea.

【 授权许可】

CC BY   
© Raji et al; licensee BioMed Central Ltd. 2013