Prevention of salt-dependent cardiac remodeling and enhanced gene expression in stroke-prone hypertensive rats by the long-acting calcium channel blocker lacidipine


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Abstract

ObjectiveTo analyze the effect of the long-acting calcium channel blocker lacidipine on cardiovascular remodeling induced by salt loading in a genetic model of hypertension.DesignWe examined the influence of threshold doses of lacidipine, with little blood-pressure lowering effect, on cardiac weight and gene expression in stroke-prone spontaneously hypertensive rats (SHRSP).MethodsSHRSPs (8–week-old) were randomly allocated to four groups: control, salt-loaded SHRSP and salt-loaded SHRSP treated with lacidipine at 0.3 and 1 mg/kg per day. Systolic blood pressure was measured by the tail-cuff method. At the end of 6 weeks of treatment, ventricles were collected and weighed. Ventricular messenger RNA was extracted and subjected to Northern blot analysis.ResultsLacidipine (0.3 mg/kg per day) not only prevented the salt-dependent cardiac hypertrophy and the slight increase in systolic blood pressure induced by salt, but also prevented, largely or completely, salt-dependent increases in ventricular levels of several gene products: skeletal and cardiac α-actin, β-myosin heavy chain (β-MHC), type I collagen, long-lasting (L)-type calcium channel and preproendothelin-1. At a higher dose of 1 mg/kg per day, lacidipine further decreased systolic blood pressure below the level of control SHRSP, completely prevented salt-dependent overexpression of the β-MHC gene and markedly attenuated salt-dependent overexpression of the transforming growth factor-β1 gene.ConclusionsLacidipine prevents the cardiac remodeling and enhanced gene expression induced by salt loading in SHRSP at doses that only minimally affect the high systolic blood pressure.

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