title: In vitro and in vivo pharmacology of a structurally novel Na+-H+ exchange inhibitor, T-162559.
abstract: 1. We investigated the inhibitory effects of a non-acylguanidine Na(+)-H(+) exchange (NHE) inhibitor, T-162559 ((5E,7S)-[7-(5-fluoro-2-methylphenyl)-4-methyl-7,8-dihydro-5(6H)-quinolinylideneamino] guanidine dimethanesulphonate), on NHE-1, and its cardioprotective effect against ischaemia and reperfusion injury in rats and rabbits. 2. T-162559 inhibited human platelet NHE-1 in a concentration-dependent manner, with an IC(50) value of 13+/-3 nmol l(-1), making it 16 and three times more potent than cariporide IC(50): 209+/-75 nmol l(-1), P<0.01) and eniporide (IC(50): 40+/-11 nmol l(-1), P=0.066), respectively. T-162559 also inhibited rat NHE-1 with an IC(50) value of 14+/-2 nmol l(-1), which was five and three times lower than that of cariporide (IC(50): 75+/-7 nmol l(-1), P<0.01) and eniporide (IC(50): 44+/-2 nmol l(-1), P<0.01), respectively. 3. T-162559 inhibited, in a concentration-dependent manner, the reduction in cardiac contractility, progression of cardiac contracture, and increase in lactate dehydrogenase release after global ischaemia and reperfusion in perfused rat hearts. The inhibitory effects of T-162559 were observed at a lower concentration range (10 - 100 nmol l(-1)) than with cariporide and eniporide. T-162559 did not alter basal cardiac contractility or coronary flow after reperfusion, suggesting that it exerts direct cardioprotective effects on the heart. 4. Intravenous administration of T-162559 (0.03 and 0.1 mg kg(-1)) significantly inhibited the progression of myocardial infarction induced by left coronary artery occlusion and reperfusion in rabbits; the infarct size normalized by area at risk was 74+/-6% in the vehicle group, and 47+/-5% and 51+/-7% in the T-162559-0.03 mg kg(-1) and T-162559-0.1 mg kg(-1) groups (both P<0.05), respectively. 5. These results indicate that the new structural NHE-1 inhibitor T-162559 is more potent than cariporide and eniporide and possesses a cardioprotective effect against ischaemia and reperfusion injury in rat and rabbit models.
authors.affiliation: Pharmacology Research Laboratories I, Takeda Chemical Industries, LTD., Osaka 532-8686, Japan. kusumoto_keiji@takeda.co.jp
authors.forename: Keiji
authors.initials: K
authors.lastname: Kusumoto
authors.forename: Hideki
authors.initials: H
authors.lastname: Igata
authors.forename: Akemi
authors.initials: A
authors.lastname: Abe
authors.forename: Shota
authors.initials: S
authors.lastname: Ikeda
authors.forename: Ayako
authors.initials: A
authors.lastname: Tsuboi
authors.forename: Eikoh
authors.initials: E
authors.lastname: Imamiya
authors.forename: Shoji
authors.initials: S
authors.lastname: Fukumoto
authors.forename: Mitsuru
authors.initials: M
authors.lastname: Shiraishi
authors.forename: Toshifumi
authors.initials: T
authors.lastname: Watanabe
mesh_terms: D000818:Animals; D001792:Blood Platelets / Q000187:drug effects / Q000378:metabolism; D002316:Cardiotonic Agents / Q000008:administration & dosage / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D006146:Guanidines / Q000008:administration & dosage* / Q000737:chemistry / Q000494:pharmacology*; D006801:Humans; D066298:In Vitro Techniques; D007275:Injections, Intravenous; D008297:Male; D009203:Myocardial Infarction / Q000473:pathology / Q000517:prevention & control; D017202:Myocardial Ischemia / Q000188:drug therapy; D015428:Myocardial Reperfusion Injury / Q000188:drug therapy; D011804:Quinolines / Q000008:administration & dosage* / Q000737:chemistry / Q000494:pharmacology*; D011817:Rabbits; D051381:Rats; D017208:Rats, Wistar; D017923:Sodium-Hydrogen Exchangers / Q000037:antagonists & inhibitors*; D013450:Sulfones / Q000494:pharmacology
chemical_list: C433465:(7-(5-fluoro-2-methylphenyl)-4-methyl-7,8-dihydro-5(6H)-quinolinylideneamino)guanidine; D002316:Cardiotonic Agents; D006146:Guanidines; D011804:Quinolines; D017923:Sodium-Hydrogen Exchangers; D013450:Sulfones; C093373:cariporide; C118397:eniporide