1. Ranolazine prevents INaL enhancement and blunts myocardial remodelling in a model of pulmonary hypertension.
- Author
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Rocchetti M, Sala L, Rizzetto R, Staszewsky LI, Alemanni M, Zambelli V, Russo I, Barile L, Cornaghi L, Altomare C, Ronchi C, Mostacciuolo G, Lucchetti J, Gobbi M, Latini R, and Zaza A
- Subjects
- Animals, Calcium Signaling drug effects, Collagen metabolism, Disease Models, Animal, Fibrosis, Hypertension, Pulmonary chemically induced, Hypertension, Pulmonary metabolism, Hypertension, Pulmonary pathology, Hypertension, Pulmonary physiopathology, Hypertrophy, Right Ventricular etiology, Hypertrophy, Right Ventricular metabolism, Hypertrophy, Right Ventricular pathology, Hypertrophy, Right Ventricular physiopathology, Male, Membrane Potentials, Monocrotaline, Myocytes, Cardiac metabolism, Myocytes, Cardiac pathology, Myosin Heavy Chains metabolism, Pulmonary Artery drug effects, Pulmonary Artery metabolism, Pulmonary Artery physiopathology, Ranolazine, Rats, Rats, Sprague-Dawley, Sodium Channels metabolism, Time Factors, Vascular Remodeling drug effects, Vascular Resistance drug effects, Acetanilides pharmacology, Hypertension, Pulmonary drug therapy, Hypertrophy, Right Ventricular prevention & control, Myocytes, Cardiac drug effects, Piperazines pharmacology, Sodium metabolism, Sodium Channel Blockers pharmacology, Sodium Channels drug effects, Ventricular Function, Right drug effects, Ventricular Remodeling drug effects
- Abstract
Aims: Pulmonary arterial hypertension (PAH) reflects abnormal pulmonary vascular resistance and causes right ventricular (RV) hypertrophy. Enhancement of the late sodium current (INaL) may result from hypertrophic remodelling. The study tests whether: (i) constitutive INaL enhancement may occur as part of PAH-induced myocardial remodelling; (ii) ranolazine (RAN), a clinically available INaL blocker, may prevent constitutive INaL enhancement and PAH-induced myocardial remodelling., Methods and Results: PAH was induced in rats by a single monocrotaline (MCT) injection [60 mg/kg intraperitoneally (i.p.)]; studies were performed 3 weeks later. RAN (30 mg/kg bid i.p.) was administered 48 h after MCT and washed-out 15 h before studies. MCT increased RV systolic pressure and caused RV hypertrophy and loss of left ventricular (LV) mass. In the RV, collagen was increased; myocytes were enlarged with T-tubule disarray and displayed myosin heavy chain isoform switch. INaL was markedly enhanced; diastolic Ca(2+) was increased and Ca(2+) release was facilitated. K(+) currents were down-regulated and APD was prolonged. In the LV, INaL was enhanced to a lesser extent and cell Ca(2+) content was strongly depressed. Electrical remodelling was less prominent than in the RV. RAN completely prevented INaL enhancement and limited most aspects of PAH-induced remodelling, but failed to affect in vivo contractile performance. RAN blunted the MCT-induced increase in RV pressure and medial thickening in pulmonary arterioles., Conclusion: PAH induced remodelling with chamber-specific aspects. RAN prevented constitutive INaL enhancement and blunted myocardial remodelling. Partial mechanical unloading, resulting from an unexpected effect of RAN on pulmonary vasculature, might contribute to this effect., (Published on behalf of the European Society of Cardiology. All rights reserved. © The Author 2014. For permissions please email: journals.permissions@oup.com.)
- Published
- 2014
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