1400W dihydrochloride

1400W dihydrochloride is a potent and selective inhibitor of inducible nitric oxide synthase with Kd value of 7 nM [1].

Inducible nitric oxide synthase (iNOS) is an enzyme catalyzing the production of nitric oxide (NO) and is involved in immune response. iNOS produces NO as an immune defense mechanism.

1400W dihydrochloride is an extremely slowly reversible and selective iNOS inhibitor [1]. 1400W inhibited iNOS with Kd value of 7 nM and rapidly reversibly inhibited human neuronal NOS (nNOS) and endothelial NOS (eNOS) with Ki values of 2 and 50 μM, respectively. L-arginine was a competitive inhibitor of 1400W with Ks value of 3.0 μM [1].

In an endotoxin-induced vascular injury rat model, 1400W exhibited 50-fold more potent selectivity against iNOS than eNOS [1]. In focal cerebral ischaemia rats, 1400W (20 mg/kg) inhibited neurological dysfunction and weight loss and significantly decreased ischaemic lesion volume by 31%. Also, 1400W reduced iNOS activity by 36% in the infarct [2]. In the EMT6 murine mammary adenocarcinoma, 1400W (10 or 12 mg/kg/h) significantly reduced tumor weight and inhibited iNOS activity [3].

References:
[1].  Garvey EP, Oplinger JA, Furfine ES, et al. 1400W is a slow, tight binding, and highly selective inhibitor of inducible nitric-oxide synthase in vitro and in vivo. J Biol Chem, 1997, 272(8): 4959-4963.
[2].  Thomsen LL, Scott JM, Topley P, et al. Selective inhibition of inducible nitric oxide synthase inhibits tumor growth in vivo: studies with 1400W, a novel inhibitor. Cancer Res, 1997, 57(15): 3300-3304.
[3].  Parmentier S, Böhme GA, Lerouet D, et al. Selective inhibition of inducible nitric oxide synthase prevents ischaemic brain injury. Br J Pharmacol, 1999, 127(2): 546-552.

Ropivacaine-induced contraction is attenuated by both endothelial nitric oxide and voltage-dependent potassium channels in isolated rat aortae.[Pubmed:24350275]

Biomed Res Int. 2013;2013:565271.

This study investigated endothelium-derived vasodilators and potassium channels involved in the modulation of ropivacaine-induced contraction. In endothelium-intact rat aortae, ropivacaine concentration-response curves were generated in the presence or absence of the following inhibitors: the nonspecific nitric oxide synthase (NOS) inhibitor N (omega) -nitro-L-arginine methyl ester (L-NAME), the neuronal NOS inhibitor N (omega) -propyl-L-arginine hydrochloride, the inducible NOS inhibitor 1400W dihydrochloride, the nitric oxide-sensitive guanylyl cyclase (GC) inhibitor ODQ, the NOS and GC inhibitor methylene blue, the phosphoinositide-3 kinase inhibitor wortmannin, the cytochrome p450 epoxygenase inhibitor fluconazole, the voltage-dependent potassium channel inhibitor 4-aminopyridine (4-AP), the calcium-activated potassium channel inhibitor tetraethylammonium (TEA), the inward-rectifying potassium channel inhibitor barium chloride, and the ATP-sensitive potassium channel inhibitor glibenclamide. The effect of ropivacaine on endothelial nitric oxide synthase (eNOS) phosphorylation in human umbilical vein endothelial cells was examined by western blotting. Ropivacaine-induced contraction was weaker in endothelium-intact aortae than in endothelium-denuded aortae. L-NAME, ODQ, and methylene blue enhanced ropivacaine-induced contraction, whereas wortmannin, N (omega) -propyl-L-arginine hydrochloride, 1400W dihydrochloride, and fluconazole had no effect. 4-AP and TEA enhanced ropivacaine-induced contraction; however, barium chloride and glibenclamide had no effect. eNOS phosphorylation was induced by ropivacaine. These results suggest that ropivacaine-induced contraction is attenuated primarily by both endothelial nitric oxide and voltage-dependent potassium channels.

Effects of selective and non-selective inhibitors of nitric oxide synthase on morphine- and endomorphin-1-induced analgesia in acute and neuropathic pain in rats.[Pubmed:24035921]

Neuropharmacology. 2013 Dec;75:445-57.

Nitric oxide (NO) has been reported to be involved in the mechanisms of pain generation throughout the nervous system. We examined the effects of intrathecally (i.t.) administered nitric oxide synthase (NOS) inhibitors on the antinociceptive effects of morphine and endomorphin-1 during acute pain and in chronic constriction injury (CCI)-exposed rats. We used N(G)-nitro-l-arginine methyl ester (l-NAME), a non-selective NOS inhibitor; 7-nitroindazole (7-NI) or 1-(2-trifluoromethyl-phenyl)-imidazole (TRIM), selective inhibitors of neuronal NOS (NOS1); and 1400W dihydrochloride, a selective inhibitor of inducible NOS (NOS2). Morphine (0.5-2.5 mug) and endomorphin-1 (2.5-20 mug) in acute pain and morphine (10-40 mug) and endomorphin-1 (5-20 mug) after CCI-injury were combined with NOS inhibitors. For acute pain, the ED50 for endomorphin-1 (7.1 mug) was higher than that of morphine (1.3 mug) in the tail-flick test. For neuropathic pain, the ED50 value for morphine was much higher (43.2 mug) than that of endomorphin-1 (9.2 mug) in von Frey test. NOS inhibitors slightly influenced pain thresholds in both pain models. Moreover, in neuropathic pain, the effects of morphine were more potentiated by L-NAME, TRIM, 7-NI and 1400W (12x, 8.6x, 4.1x and 5.3x, respectively) than were the effects of endomorphin-1 (2.7x, 4.3x, 3.4x and 2.1x, respectively) in the von Frey test. Minocycline which is known to enhance the efficiency of morphine in neuropathic pain, decreased the mRNA expression of NOS1 in the DRG and NOS2 and C1q in the spinal cord after CCI. Both NOS2 and IBA-1 protein levels in the spinal cord and NOS1, NOS2 and IBA1 protein levels in DRG decreased after minocycline administration. In conclusion, our results provide evidence that both neuronal and non-neuronal NOS/NO pathways contribute to the behavioural pain responses evoked by nerve injury. The NOS inhibitors regardless of the type of pain enhanced morphine antinociception and, to a lesser extent, altered the effects of endomorphin-1, an opioid ligand with a peptidergic structure.

The dynamic detection of NO during stroke and reperfusion in vivo.[Pubmed:19408167]

Brain Inj. 2009 May;23(5):450-8.

PURPOSE: Nitric oxide (NO) has been implicated as a mediator of synaptic transmission and a pathological factor in stroke/reperfusion. The purpose of this study was to detect the change of NO concentration in rat hippocampus during global cerebral ischemia and reperfusion in vivo and to reveal effects of different NO synthases (NOS). METHOD: In the present study, the real-time record of NO levels in rat hippocampus was obtained by using a NO sensor during the global cerebral ischemia and the initial stage of reperfusion. The effects of two inhibitors of NOS on NO concentration were also observed. The two inhibitors were respectively administrated intravenously at the onset of reperfusion and 1 hour later. RESULTS: The change of the NO concentration in the initial stage of reperfusion was 0.768 +/- 0.029 microM. 7-nitroindazole (7-NI, inhibitor of nNOS) had a strong inhibitive effect on NO synthesis at both time points, while 1400W dihydrochloride (1400W, inhibitor of iNOS) had no significant effect on the NO synthesis. CONCLUSIONS: The in vivo detection revealed the real dynamic change of NO concentration, which is much more reliable than the in vitro method. The results showed that, during the initial stage of reperfusion, NO biosynthesis was mainly in an nNOS-dependent manner. Thus, the toxicity of NO in this process had a close relationship with the activity of nNOS but not iNOS.

Selective inhibition of inducible nitric oxide synthase prevents ischaemic brain injury.[Pubmed:10385257]

Br J Pharmacol. 1999 May;127(2):546-52.

1. The aim of this study was to investigate the effect of N-(3-(aminomethyl)benzyl)acetamidine (1400W), a selective inhibitor of inducible calcium-independent nitric oxide synthase (iNOS), on the functional and histopathological outcomes of experimental transient focal cerebral ischaemia in rats. 2. Transient ischaemia was produced by the occlusion for 2 h of both the left middle cerebral artery and common carotid artery. Treatments with 1400W (20 mg kg(-1)) or vehicle were started 18 h after occlusion of the arteries and consisted in seven subcutaneous injections at 8 h interval. Ischaemic outcomes and NOS activities (constitutive and calcium-independent NOS) were evaluated 3 days after ischaemia. 3. 1400W significantly reduced ischaemic lesion volume by 31%, and attenuated weight loss and neurological dysfunction. 4. 1400W attenuated the calcium-independent NOS activity in the infarct by 36% without affecting the constitutive NOS activity. 5. These findings suggest that iNOS activation contributes to tissue damage and that selective inhibitors of this isoform may be of interest for the treatment of stroke.

1400W is a slow, tight binding, and highly selective inhibitor of inducible nitric-oxide synthase in vitro and in vivo.[Pubmed:9030556]

J Biol Chem. 1997 Feb 21;272(8):4959-63.

N-(3-(Aminomethyl)benzyl)acetamidine (1400W) was a slow, tight binding inhibitor of human inducible nitric- oxide synthase (iNOS). The slow onset of inhibition by 1400W showed saturation kinetics with a maximal rate constant of 0.028 s-1 and a binding constant of 2.0 microM. Inhibition was dependent on the cofactor NADPH. L-Arginine was a competitive inhibitor of 1400W binding with a Ks value of 3.0 microM. Inhibited enzyme did not recover activity after 2 h. Thus, 1400W was either an irreversible inhibitor or an extremely slowly reversible inhibitor of human iNOS with a Kd value

Selective inhibition of inducible nitric oxide synthase inhibits tumor growth in vivo: studies with 1400W, a novel inhibitor.[Pubmed:9242464]

Cancer Res. 1997 Aug 1;57(15):3300-4.

We have investigated the effect of N-(3-(aminomethyl)benzyl)acetamidine (1400W), a novel and highly selective inhibitor for inducible NOS (iNOS), on in vivo growth of solid tumors expressing iNOS. For the EMT6 murine mammary adenocarcinoma, in which iNOS is expressed in the tumor cells, continuous infusion of 1400W for 6 days at 10 or 12 mg/kg(-1)/h(-1) resulted in significant reduction in tumor weight (357 +/- 46 and 466 +/- 70 mg, respectively) compared with that of controls [726 +/- 65 (P < 0.001) and 796 +/- 88 mg (P < 0.02), respectively]. Reduced growth was also observed for a human tumor xenograft (colon adenocarcinoma DLD-1) genetically engineered to express iNOS constitutively and treated for 13 days with 6 mg/kg(-1)/h(-1) 1400W compared with controls (tumor weights 340 +/- 50 and 580 +/- 90 mg, respectively; P < 0.03). Growth of the parental DLD-1 clone was not altered with this treatment compared with that of controls (tumor weights 170 +/- 10 and 240 +/- 50 mg, respectively). Inhibition of iNOS in vivo was confirmed by decreases in plasma nitrite + nitrate concentrations in treated animals compared with that of controls (63-83% decreases for all experiments) and was supported by plasma and tumor concentrations of 1400W that were equivalent and 2.6-4.9 times higher than the EC50 previously reported for iNOS in a tissue assay. For the murine colon adenocarcinoma Colon 38, in which intratumoral macrophages are the predominant source of iNOS and which had high intratumoral arginine concentrations, 1400W treatment had no effect on growth or plasma nitrate + nitrate. Future studies with more potent selective iNOS inhibitors and a wider range of tumors may determine whether iNOS inhibitors could represent a novel approach to the treatment of cancer. These studies confirm that nitric oxide production in tumors plays a role in promoting their growth, rather than a role as a host defense mechanism in inhibiting growth.