ABSTRACT
Aldosterone plays a central role in the development of cardiac pathological states involving ion transport imbalances, especially sodium transport. We have previously demonstrated a cardioprotective effect of proanthocyanidins in aldosterone-treated rats. Our objective was to investigate for the first time the effect of proanthocyanidins on serum and glucocorticoid-regulated kinase 1 (SGK1), epithelial Na+ channel (γ-ENaC), neuronal precursor cells expressed developmentally down-regulated 4-2 (Nedd4-2) and phosphoNedd4-2 protein expression in the hearts of aldosterone-treated rats. Male Wistar rats received aldosterone (1mg kg-1day-1)+1% NaCl for 3weeks. Half of the animals in each group were simultaneously treated with the proanthocyanidins-rich extract (80% w/w) (PRO80, 5mg kg-1day-1). Hypertension and diastolic dysfunction induced by aldosterone were abolished by treatment with PRO80. Expression of fibrotic, inflammatory and oxidative mediators were increased by aldosterone-salt administration and blunted by PRO80. Antioxidant capacity was improved by PRO80. The up-regulated aldosterone mediator SGK1, ENaC and p-Nedd4-2/total Nedd4-2 ratio were blocked by PRO80. PRO80 blunted aldosterone-mineralocorticoid-mediated up-regulation of ENaC provides new mechanistic insight of the beneficial effect of proanthocyanidins preventing the cardiac alterations induced by aldosterone excess.
Subject(s)
Dietary Supplements , Endosomal Sorting Complexes Required for Transport/antagonists & inhibitors , Epithelial Sodium Channels/metabolism , Heart Ventricles/metabolism , Immediate-Early Proteins/antagonists & inhibitors , Proanthocyanidins/therapeutic use , Protein Serine-Threonine Kinases/antagonists & inhibitors , Ubiquitin-Protein Ligases/antagonists & inhibitors , Ventricular Dysfunction, Left/prevention & control , Animals , Anti-Inflammatory Agents, Non-Steroidal/therapeutic use , Antihypertensive Agents/therapeutic use , Antioxidants/therapeutic use , Biomarkers/metabolism , Cardiomegaly/etiology , Cardiomegaly/prevention & control , Cardiotonic Agents/therapeutic use , Endosomal Sorting Complexes Required for Transport/agonists , Endosomal Sorting Complexes Required for Transport/metabolism , Epithelial Sodium Channel Agonists/antagonists & inhibitors , Epithelial Sodium Channel Agonists/metabolism , Epithelial Sodium Channel Blockers/therapeutic use , Epithelial Sodium Channels/chemistry , Fibrosis , Heart Ventricles/immunology , Heart Ventricles/pathology , Heart Ventricles/physiopathology , Hypertension/etiology , Hypertension/prevention & control , Immediate-Early Proteins/agonists , Immediate-Early Proteins/metabolism , Male , Mineralocorticoid Receptor Antagonists/therapeutic use , Nedd4 Ubiquitin Protein Ligases , Oxidative Stress , Protein Serine-Threonine Kinases/metabolism , Rats, Wistar , Ubiquitin-Protein Ligases/metabolism , Ventricular Dysfunction, Left/metabolism , Ventricular Dysfunction, Left/pathology , Ventricular Dysfunction, Left/physiopathologyABSTRACT
Cholecystokinin (CCK) is a peptide that acts as a peripheral hormone and as a central neurotransmitter. To date, two distinct receptors have been identified for CCK using structural and operational criteria; CCK1 and CCK2 (formerly CCKA and CCKB, respectively). In addition, there is the gastrin receptor found in the stomach which has a high structural similarity to the CCK2 receptor, but which displays a different pharmacology. This unit presents two methods for the quantification of selective agonists and antagonists at CCK1 receptors and an assay for CCK2 receptors. In the first tissue, the guinea-pig ileum longitudinal muscle with myenteric plexus, both CCK1 and CCK2 receptors are present in the same preparation. Each receptor is distinguished in this assay using selective agonists and antagonists against the unwanted receptor subtype. The second preparation, the guinea-pig gallbladder, is a classical preparation for studying CCK1 receptor-active compounds in the absence of CCK2 sites.
