title: Amlodipine inhibits TNF-alpha production and attenuates cardiac dysfunction induced by lipopolysaccharide involving PI3K/Akt pathway.
abstract: Calcium channel blockers (CCBs) are widely used in the therapy of cardiovascular diseases. Recent studies have shown that several CCBs exerted distinct anti-inflammatory effect in myocardial dysfunction models. The purpose of the present study was to evaluate therapeutic effect and possible mechanism of action of amlodipine, one of the widely used CCBs, on rat cardiac dysfunction during sepsis induced by lipopolysaccharide (LPS). Pretreatment of the rats with amlodipine (10 or 30 mg/kg, i.v.) delayed the fall of mean arterial blood pressure caused by LPS. Amlodipine also significantly inhibited the elevation of plasma tumor necrosis factor alpha (TNF-alpha) and decreased levels of inducible nitric oxide synthase (iNOS) in response to LPS challenge. To investigate the mechanism of the action of amlodipine, neonatal rat cardiomyocytes were used as a model. Amlodipine concentration-dependently decreased the release of TNF-alpha and iNOS protein expression, and suppressed the degradation and phosphorylation of inhibitor of kappaB-alpha (IkappaB-alpha) in LPS-activated neonatal rat cardiomyocytes. Further studies revealed that amlodipine markedly activated phosphatidylinositiol 3-kinase (PI3K) and Akt, downstream of the PI3K signal cascade. Application of PI3K inhibitors, wortmannin and LY294002 attenuated the depression of TNF-alpha and iNOS expression by amlodipine in LPS-induced cardiomyocytes. These findings may explain some cardioprotective effects of amlodipine in LPS-mediated sepsis and suggest that the inhibition of TNF-alpha and iNOS expression by amlodipine is, at least in part, dependent on PI3K/Akt signaling pathway.
authors.affiliation: Department of Pharmacology, the Fourth Military Medical University, Xi'an, Shaanxi, China. lixiaoqiang@hotmail.com
authors.forename: Xiao-Qiang
authors.initials: XQ
authors.lastname: Li
authors.forename: Wei
authors.initials: W
authors.lastname: Cao
authors.forename: Tao
authors.initials: T
authors.lastname: Li
authors.forename: Ai-Guo
authors.initials: AG
authors.lastname: Zeng
authors.forename: Li-Li
authors.initials: LL
authors.lastname: Hao
authors.forename: Xiao-Nan
authors.initials: XN
authors.lastname: Zhang
authors.forename: Qi-Bing
authors.initials: QB
authors.lastname: Mei
mesh_terms: D017311:Amlodipine / Q000494:pharmacology* / Q000627:therapeutic use; D000818:Animals; D000893:Anti-Inflammatory Agents / Q000494:pharmacology / Q000627:therapeutic use; D002121:Calcium Channel Blockers / Q000494:pharmacology* / Q000627:therapeutic use; D002478:Cells, Cultured; D005786:Gene Expression Regulation / Q000187:drug effects / Q000276:immunology; D006331:Heart Diseases / Q000139:chemically induced / Q000188:drug therapy* / Q000235:genetics / Q000276:immunology / Q000473:pathology; D008070:Lipopolysaccharides / Q000009:adverse effects; D008297:Male; D032383:Myocytes, Cardiac / Q000187:drug effects* / Q000276:immunology / Q000378:metabolism / Q000473:pathology; D052247:Nitric Oxide Synthase Type II / Q000235:genetics / Q000276:immunology / Q000378:metabolism*; D019869:Phosphatidylinositol 3-Kinases / Q000276:immunology / Q000378:metabolism; D051057:Proto-Oncogene Proteins c-akt / Q000276:immunology / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D018805:Sepsis / Q000139:chemically induced / Q000188:drug therapy / Q000235:genetics / Q000276:immunology / Q000473:pathology; D015398:Signal Transduction / Q000187:drug effects / Q000276:immunology; D014409:Tumor Necrosis Factor-alpha / Q000235:genetics / Q000276:immunology / Q000378:metabolism
chemical_list: D000893:Anti-Inflammatory Agents; D002121:Calcium Channel Blockers; D008070:Lipopolysaccharides; D014409:Tumor Necrosis Factor-alpha; D017311:Amlodipine; D052247:Nitric Oxide Synthase Type II; D019869:Phosphatidylinositol 3-Kinases; D051057:Proto-Oncogene Proteins c-akt