Pharmacological characterization of KLYP961, a dual inhibitor of inducible and neuronal nitric-oxide synthases.

Abstract

Nitric oxide (NO) derived from neuronal nitric-oxide synthase (nNOS) and inducible nitric-oxide synthase (iNOS) plays a key role in various pain and inflammatory states. KLYP961 (4-((2-cyclobutyl-1H-imidazo[4,5-b]pyrazin-1-yl)methyl)-7,8-difluoroquinolin-2(1H)-one) inhibits the dimerization, and hence the enzymatic activity of human, primate, and murine iNOS and nNOS (IC(50) values 50-400 nM), with marked selectivity against endothelial nitric-oxide synthase (IC(50) >15,000 nM). It has ideal drug like-properties, including excellent rodent and primate pharmacokinetics coupled with a minimal off-target activity profile. In mice, KLYP961 attenuated endotoxin-evoked increases in plasma nitrates, a surrogate marker of iNOS activity in vivo, in a sustained manner (ED(50) 1 mg/kg p.o.). KLYP961 attenuated pain behaviors in a mouse formalin model (ED(50) 13 mg/kg p.o.), cold allodynia in the chronic constriction injury model (ED(50) 25 mg/kg p.o.), or tactile allodynia in the spinal nerve ligation model (ED(50) 30 mg/kg p.o.) with similar efficacy, but superior potency relative to gabapentin, pregabalin, or duloxetine. Unlike morphine, the antiallodynic activity of KLYP961 did not diminish upon repeated dosing. KLYP961 also attenuated carrageenin-induced edema and inflammatory hyperalgesia and writhing response elicited by phenylbenzoquinone with efficacy and potency similar to those of celecoxib. In contrast to gabapentin, KLYP961 did not impair motor coordination at doses as high as 1000 mg/kg p.o. KLYP961 also attenuated capsaicin-induced thermal allodynia in rhesus primates in a dose-related manner with a minimal effective dose (≤ 10 mg/kg p.o.) and a greater potency than gabapentin. In summary, KLYP961 represents an ideal tool with which to probe the physiological role of NO derived from iNOS and nNOS in human pain and inflammatory states.

• Authors: Kent T Symons, Phan M Nguyen, Mark E Massari, John V Anzola, Lena M Staszewski, Li Wang, Nahid Yazdani, Steven Dorow, Jerry Muhammad, Marciano Sablad, Natasha Rozenkrants, Celine Bonefous, Joseph E Payne, Peter J Rix, Andrew K Shiau, Stewart A Noble, Nicholas D Smith, Christian A Hassig, Yan Zhang, Tadimeti S Rao
• Journal: The Journal of pharmacology and experimental therapeutics (J Pharmacol Exp Ther) Vol. 336 Issue 2 Pg. 468-78 (Feb 2011) ISSN: 1521-0103 [Electronic] United States
• PMID: 21036913 (Publication Type: Journal Article)

Chemical References

• 4-((2-cyclobutyl-1H-imidazo(4,5-b)pyrazin-1-yl)methyl)-7,8-difluoroquinolin-2(1H)-one
• Analgesics
• Anti-Inflammatory Agents
• Cytochrome P-450 Enzyme Inhibitors
• Enzyme Inhibitors
• Fluoroquinolones
• Pyrazines
• Nitric Oxide Synthase Type I
• Nitric Oxide Synthase Type II

Topics

• Analgesics (pharmacology)
• Animals
• Anti-Inflammatory Agents (pharmacology)
• Cells, Cultured
• Cytochrome P-450 Enzyme Inhibitors
• Enzyme Inhibitors (pharmacokinetics, pharmacology, toxicity)
• Fluoroquinolones (pharmacokinetics, pharmacology, toxicity)
• Gastrointestinal Transit (drug effects)
• Humans
• Macaca mulatta
• Male
• Mice
• Mice, Inbred BALB C
• Mice, Inbred C57BL
• Motor Activity (drug effects)
• Nitric Oxide Synthase Type I (antagonists & inhibitors)
• Nitric Oxide Synthase Type II (antagonists & inhibitors)
• Protein Multimerization
• Pyrazines (pharmacokinetics, pharmacology, toxicity)