title: Mechanisms of the beneficial effects of vitamin B6 and pyridoxal 5-phosphate on cardiac performance in ischemic heart disease.
abstract: Although vitamin B6 and its metabolite, pyridoxal 5'-phosphate (PLP), have been shown to exert beneficial effects in ischemic heart disease, the mechanisms of their action are not fully understood. Some studies have shown that ventricular arrhythmias and mortality upon the occlusion of coronary artery were attenuated by pretreatment of animals with PLP. Furthermore, ischemia-reperfusion-induced abnormalities in cardiac performance and defects in sarcoplasmic reticular Ca2+-transport activities were decreased by PLP. The increase in cardiac contractile activity of isolated heart by ATP was reduced by PLP, unlike propranolol, whereas that by isoproterenol was not depressed by PLP. ATP-induced increase in [Ca2+]i, unlike KCl-induced increase in [Ca2+]i in cardiomyocytes was depressed by PLP. Both high- and low-affinity sites for ATP binding in sarcolemmal membranes were also decreased by PLP. These observations support the view that PLP may produce cardioprotective effects in ischemic heart disease by attenuating the occurrence of intracellular Ca2+ overload due to the blockade of purinergic receptors.
authors: Institute of Cardiovascular Sciences, St. Boniface Hospital Research, Faculty of Medicine, Department of Physiology, University of Manitoba, Winnipeg, Manitoba, R2H 2A6 Canada. nsdhalla@sbrc.ca
authors: Naranjan S
authors: NS
authors: Dhalla
authors: Satoshi
authors: S
authors: Takeda
authors: Vijayan
authors: V
authors: Elimban
mesh_terms: D000818:Animals; D002316:Cardiotonic Agents / Q000378:metabolism / Q000494:pharmacology / Q000627:therapeutic use; D006321:Heart / Q000187:drug effects / Q000502:physiology; D017202:Myocardial Ischemia / Q000188:drug therapy* / Q000378:metabolism / Q000473:pathology; D011732:Pyridoxal Phosphate / Q000378:metabolism / Q000494:pharmacology / Q000627:therapeutic use*; D015427:Reperfusion Injury / Q000188:drug therapy / Q000378:metabolism / Q000473:pathology; D025101:Vitamin B 6 / Q000378:metabolism / Q000494:pharmacology / Q000627:therapeutic use*; D026681:Vitamin B 6 Deficiency / Q000188:drug therapy / Q000378:metabolism / Q000473:pathology
chemical_list: D002316:Cardiotonic Agents; D011732:Pyridoxal Phosphate; D025101:Vitamin B 6