N-Phenylamidines as selective inhibitors of human neuronal nitric oxide synthase: structure-activity studies and demonstration of in vivo activity.

Article Details

Citation

Collins JL, Shearer BG, Oplinger JA, Lee S, Garvey EP, Salter M, Duffy C, Burnette TC, Furfine ES

N-Phenylamidines as selective inhibitors of human neuronal nitric oxide synthase: structure-activity studies and demonstration of in vivo activity.

J Med Chem. 1998 Jul 16;41(15):2858-71.

PubMed ID
9667974 [ View in PubMed
]
Abstract

Selective inhibition of the neuronal isoform of nitric oxide synthase (NOS) compared to the endothelial and inducible isoforms may be required for treatment of neurological disorders caused by excessive production of nitric oxide. Recently, we described N-(3-(aminomethyl)benzyl)acetamidine (13) as a slow, tight-binding inhibitor, highly selective for human inducible nitric oxide synthase (iNOS). Removal of a single methylene bridge between the amidine nitrogen and phenyl ring to give N-(3-(aminomethyl)phenyl)acetamidine (14) dramatically altered the selectivity to give a neuronal selective nitric oxide synthase (nNOS) inhibitor. Part of this large shift in selectivity was due to 14 being a rapidly reversible inhibitor of iNOS in contrast to the essentially irreversible inhibition of iNOS observed with 13. Structure-activity studies revealed that a basic amine functionality tethered to an aromatic ring and a sterically compact amidine are key pharmacophores for this class of NOS inhibitors. Maximal nNOS inhibition potency was achieved with N-(3-(aminomethyl)phenyl)-2-furanylamidine (77) (Ki-nNOS = 0.006 microM; Ki-eNOS = 0.35 microM; Ki-iNOS = 0.16 microM). Finally, alpha-fluoro-N-(3-(aminomethyl)phenyl)acetamidine (74) (Ki-nNOS = 0. 011 microM; Ki-eNOS = 1.1 microM; Ki-iNOS = 0.48 microM) had excellent brain penetration and inhibited nNOS in a rat brain slice assay as well as in the rat brain (cerebellum) in vivo. Thus, N-phenylamidines should be useful in validating the role of nNOS in neurological disorders.

DrugBank Data that Cites this Article

Binding Properties
DrugTargetPropertyMeasurementpHTemperature (°C)
NitroarginineNitric oxide synthase, brainKi (nM)15N/AN/ADetails
NitroarginineNitric oxide synthase, endothelialKi (nM)30N/AN/ADetails