ENaC; uTPA; polycystin-2 (TRPP2)

A strong inhibitor of epithelial sodium channels (ENaCs) is amiloride hydrochloride dihydrate. Within fifteen to thirty minutes after injection, amiloride is significantly concentrated in the plasma. When compared to the baseline readings (n = 7), a 2 mg/kg dose of amiloride hydrochloride dihydrate has no effect on blood pressure, heart rate, mesenteric vascular resistance, or hindquarters vascular resistance. Amiloride hydrochloride dihydrate causes very little change in heart rate (-10±6 bpm/min) and arterial pressure (-1±1 mmHg) over a 2-hour period when compared to baseline values. The c-Fos activation in the area postrema (AP) exhibits a dose-related response pattern, according to the results. Amiloride hydrochloride dihydrate, even at the lowest dose of 0.1 mg/kg, is statistically different from the control rats in terms of the number of c-Fos labeled neurons at the p<0.01 level[1].

This study examined the mechanism of action of amiloride, a urokinase-type plasminogen activator receptor inhibitor, in lowering proteinuria. Podocytes were resuscitated to allow for their proliferation and were observed for morphological changes. In the in vitro experiment, control, lipopolysaccharide, and lipopolysaccharide + amiloride groups were established. The expression of urokinase-type plasminogen activator receptor (uPAR) in podocytes was detected with a flow cytometer and cell motility was detected with the transwell migration assay[2].

Epithelial sodium channels (ENaCs) are strongly expressed in the circumventricular organs (CVOs), and these structures may play an important role in sensing plasma sodium levels. Here, the potent ENaC blocker amiloride was injected intraperitoneally in rats and 2h later, the c-Fos activation pattern in the CVOs was studied. Amiloride elicited dose-related activation in the area postrema (AP) but only ~10% of the rats showed c-Fos activity in the organum vasculosum of the lamina terminalis (OVLT) and subfornical organ (SFO). Tyrosine hydroxylase-immunoreactive (catecholamine) AP neurons were activated, but tryptophan hydroxylase-immunoreactive (serotonin) neurons were unaffected. The AP projects to FoxP2-expressing neurons in the dorsolateral pons which include the pre-locus coeruleus nucleus and external lateral part of the parabrachial nucleus; both cell groups were c-Fos activated following systemic injections of amiloride. In contrast, another AP projection target--the aldosterone-sensitive neurons of the nucleus tractus solitarius which express the enzyme 11-β-hydroxysteriod dehydrogenase type 2 (HSD2) were not activated. As shown here, plasma concentrations of amiloride used in these experiments were near or below the IC50 level for ENaCs. Amiloride did not induce changes in blood pressure, heart rate, or regional vascular resistance, so sensory feedback from the cardiovascular system was probably not a causal factor for the c-Fos activity seen in the CVOs. In summary, amiloride may have a dual effect on sodium homeostasis causing a loss of sodium via the kidney and inhibiting sodium appetite by activating the central satiety pathway arising from the AP.[1]

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In the in vivo test, the urine protein volume of the model was detected at 24 h using Coomassie brilliant blue staining and the morphological changes of the podocytes were detected with immunofluorescence. The protein expression rate of uPAR in the lipopolysaccharide group was significantly higher than those in the control and lipopolysaccharide + amiloride groups (P < 0.05). The viability of cells in the lipopolysaccharide group was significantly higher than those in the control and lipopolysaccharide + amiloride groups (P < 0.05). Compared with the urine protein level in the control group at 24 h, the level in the lipopolysaccharide group increased significantly (P < 0.05), whereas compared with the urine protein level in the lipopolysaccharide group, the level in the lipopolysaccharide + amiloride group decreased (P < 0.05). uPAR expression was significantly downregulated, and the fusion of the podocyte-specific skelemin synaptopodin on the glomerulus podocytes was significantly decreased in the lipopolysaccharide + amiloride group. These results suggest that amiloride is able to reduce cell motility and thus lower proteinuria by inhibiting the expression of uPAR in podocytes.[2]

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1 mg/kg/day; subcutaneous

Rats

[1]. Miller RL, et al. Blockade of ENaCs by amiloride induces c-Fos activation of the area postrema. Brain Res. 2015 Mar 19;1601:40-51.
[2]. Xu LB, et al. Amiloride, a urokinase-type plasminogen activator receptor (uTPA) inhibitor, reduces proteinurea in podocytes. Genet Mol Res. 2015 Aug 14;14(3):9518-29.
[3]. Giamarchi A, et al. A polycystin-2 (TRPP2) dimerization domain essential for the function of heteromeric polycystin complexes. EMBO J. 2010 Apr 7;29(7):1176-91

Amiloride hydrochloride dihydrate is a hydrate that is the dihydrate of amiloride hydrochloride. It has a role as a diuretic and a sodium channel blocker. It contains an amiloride hydrochloride.
Amiloride Hydrochloride is the hydrochloride salt of amiloride, a synthetic pyrazine derivative with antikaliuretic and diuretic properties. Amiloride inhibits sodium channels located in the distal tubules and collecting ducts of the kidney, thereby preventing the absorption of sodium and increasing its excretion along with water, to produce naturesis. In response to the hypernatremic conditions in the kidney, the plasma membrane becomes hyperpolarized and electrochemical forces are reduced, which then prevents the excretion of potassium and hydrogen into the lumen.
A pyrazine compound inhibiting SODIUM reabsorption through SODIUM CHANNELS in renal EPITHELIAL CELLS. This inhibition creates a negative potential in the luminal membranes of principal cells, located in the distal convoluted tubule and collecting duct. Negative potential reduces secretion of potassium and hydrogen ions. Amiloride is used in conjunction with DIURETICS to spare POTASSIUM loss. (From Gilman et al., Goodman and Gilman's The Pharmacological Basis of Therapeutics, 9th ed, p705)

C6H8CLN7O.HCL.2H2O

302.12

301.04568

C, 23.85; H, 4.34; Cl, 23.47; N, 32.45; O, 15.89

17440-83-4

Amiloride hydrochloride;2016-88-8;Amiloride;2609-46-3

68540

Typically exists as Off-white to yellow solids at room temperature

628.1ºC at 760 mmHg

>240℃

333.7ºC

1.08E-15mmHg at 25°C

1.94

175.25

ClC1C(N([H])[H])=NC(=C(C(/N=C(\N([H])[H])/N([H])[H])=O)N=1)N([H])[H].Cl[H].O([H])[H].O([H])[H]

LTKVFMLMEYCWMK-UHFFFAOYSA-N

1S/C6H8ClN7O.ClH.2H2O/c7-2-4(9)13-3(8)1(12-2)5(15)14-6(10)11;;;/h(H4,8,9,13)(H4,10,11,14,15);1H;2*1H2

2934.99.9001

Powder      -20°C    3 years

                     4°C     2 years

In solvent   -80°C    6 months

                  -20°C    1 month

Note: Please store this product in a sealed and protected environment, avoid exposure to moisture.

Room temperature (This product is stable at ambient temperature for a few days during ordinary shipping and time spent in Customs)

Solubility in Formulation 1: ≥ 2.5 mg/mL (8.27 mM) (saturation unknown) in 10% DMSO + 40% PEG300 + 5% Tween80 + 45% Saline (add these co-solvents sequentially from left to right, and one by one), clear solution.
For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 25.0 mg/mL clear DMSO stock solution to 400 μL PEG300 and mix evenly; then add 50 μL Tween-80 to the above solution and mix evenly; then add 450 μL normal saline to adjust the volume to 1 mL.
Preparation of saline: Dissolve 0.9 g of sodium chloride in 100 mL ddH₂ O to obtain a clear solution.

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Solubility in Formulation 2: ≥ 2.5 mg/mL (8.27 mM) (saturation unknown) in 10% DMSO + 90% (20% SBE-β-CD in Saline) (add these co-solvents sequentially from left to right, and one by one), clear solution.
For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 25.0 mg/mL clear DMSO stock solution to 900 μL of 20% SBE-β-CD physiological saline solution and mix evenly.
Preparation of 20% SBE-β-CD in Saline (4°C，1 week): Dissolve 2 g SBE-β-CD in 10 mL saline to obtain a clear solution.

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Solubility in Formulation 3: ≥ 2.08 mg/mL (6.88 mM) (saturation unknown) in 10% DMSO + 90% Corn Oil (add these co-solvents sequentially from left to right, and one by one), clear solution.
For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 20.8 mg/mL clear DMSO stock solution to 900 μL of corn oil and mix evenly.

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 (Please use freshly prepared in vivo formulations for optimal results.)