title: Zoniporide: a potent and selective inhibitor of the human sodium-hydrogen exchanger isoform 1 (NHE-1).
abstract: The sodium-hydrogen exchanger isoform-1 (NHE-1) plays an important role in the myocardial response to ischemia-reperfusion; inhibition of this exchanger protects against ischemic injury, including reduction in infarct size. Herein we describe a novel, potent, and highly selective NHE-1 inhibitor, zoniporide (CP-597,396; [1-(quinolin-5-yl)-5-cyclopropyl-1H-pyrazole-4-carbonyl] guanidine). Zoniporide inhibits human NHE-1 with an IC(50) of 14 nM, has >150-fold selectivity vs. other NHE isoforms, and potently inhibits ex vivo NHE-1-dependent swelling of human platelets. This compound is well tolerated in preclinical animal models, exhibits moderate plasma protein binding, has a t(1/2) of 1.5 h in monkeys, and has one major active metabolite. In both in vitro and in vivo rabbit models of myocardial ischemia-reperfusion injury, zoniporide markedly reduced infarct size without adversely affecting hemodynamics or cardiac function. In the isolated heart (Langendorff), zoniporide elicited a concentration-dependent reduction in infarct size (EC(50) = 0.25 nM). At 50 nM it reduced infarct size by 83%. This compound was 2.5-20-fold more potent than either eniporide or cariporide (EC(50)s of 0.69 and 5.11 nM, respectively), and reduced infarct size to a greater extent than eniporide. In open chest, anesthetized rabbits, zoniporide also elicited a dose-dependent reduction in infarct size (ED(50) = 0.45 mg/kg/h) and inhibited NHE-1-mediated platelet swelling (93% inhibition at 4 mg/kg/h). Furthermore, zoniporide attenuated postischemic cardiac contractile dysfunction in conscious primates, and reduced both the incidence and duration of ischemia-reperfusion-induced ventricular fibrillation in rats. Zoniporide represents a novel class of potent and selective human NHE-1 inhibitors with potential utility for providing cardioprotection in a clinical setting.
authors.affiliation: Pfizer Global Research and Development, Groton, CT 06340, USA. w_ross_tracey@groton.pfizer.com.
authors.forename: W Ross
authors.initials: WR
authors.lastname: Tracey
authors.forename: Mary C
authors.initials: MC
authors.lastname: Allen
authors.forename: Donald E
authors.initials: DE
authors.lastname: Frazier
authors.forename: Anthony A
authors.initials: AA
authors.lastname: Fossa
authors.forename: Celeste G
authors.initials: CG
authors.lastname: Johnson
authors.forename: Ravi B
authors.initials: RB
authors.lastname: Marala
authors.forename: Delvin R
authors.initials: DR
authors.lastname: Knight
authors.forename: Angel
authors.initials: A
authors.lastname: Guzman-Perez
mesh_terms: D004791:Enzyme Inhibitors / Q000737:chemistry / Q000494:pharmacology*; D006146:Guanidines / Q000009:adverse effects / Q000737:chemistry / Q000493:pharmacokinetics / Q000494:pharmacology* / Q000633:toxicity; D006801:Humans; D015428:Myocardial Reperfusion Injury / Q000188:drug therapy / Q000503:physiopathology; D011720:Pyrazoles / Q000009:adverse effects / Q000737:chemistry / Q000493:pharmacokinetics / Q000494:pharmacology* / Q000633:toxicity; D017923:Sodium-Hydrogen Exchangers / Q000037:antagonists & inhibitors* / Q000737:chemistry
chemical_list: D004791:Enzyme Inhibitors; D006146:Guanidines; D011720:Pyrazoles; D017923:Sodium-Hydrogen Exchangers; C069139:growth factor-activatable Na-H exchanger NHE-1; C424422:zoniporide