D1 Receptor (Ki = 0.2 nM); D5 Receptor (Ki = 0.3 nM); 5-HT2C Receptor (Ki = 9.3 nM); GIRK (IC50 = 268 nM)

SCH-23390 (1 μM) treatmentoverrode the inhibitory effect of isosibiricin on BV-2 cells' LPS-induced NLRP3 expression, caspase-1, and IL-1β cleavage. SCH-23390 can undo the NLRP3/caspase-1 inflammasome pathway's inhibition caused by isosibiricin.

SCH-23390 can abolish generalized seizures evoked by the chemoconvulsants. SCH-23390 has also been used in research on other neurological conditions like psychosis and Parkinson's disease where there is evidence of a dopaminergic connection. Apart from the study of neurological disorders, SCH-23390 has been extensively used as a tool in the topographical determination of brain D1 receptors in rodents, nonhuman primates, and humans[1]. After giving a rat 0.3 mg/kg i.p., SCH-23390 is a very short-acting drug with an elimination half-life of about 25 min[1]. SCH-23390 increases dopamine-induced ductus constriction in CD-1 mouse vessels under newborn O2 conditions[5].

Since 5-HT2C receptors are positively coupled to phospholipase C (PLC), their activation was determined by depletion of membrane-bound pools of pre-labelled [3H]phosphotidylinositol ([3H]PI). Results: SCH23390 showed high affinity (Ki, 9.3 nM) at h5-HT2C sites and depleted [3H]PI with an EC50 of 2.6 nM. Its efficacy was equivalent to that of 5-HT. [3H]PI depletion elicited by SCH23390 was concentration-dependently abolished by the selective 5-HT2C antagonist, SB242,084, with a K(B) of 0.55 nM. Further, in the presence of a fixed concentration of SB242,084 (10 nM), the concentration-response curve for SCH23390 was shifted to the right without loss of maximal effect, yielding a K(B) of 0.57 nM. Conclusions: SCH23390 is a potent and high efficacy agonist at h5-HT2C receptors. Activation of 5-HT2C receptors by SCH23390 may contribute to its functional properties both in animals and in humans[2].

R-(+)-7-chloro-8-hydroxy-3-methyl-1-phenyl-2,3,4,5-tetrahydro-1H-3-benzazepine hydrochloride (SCH23390) is a widely used, highly selective antagonist of D1 dopamine receptors. While investigating the crosstalk between D1 and D3 dopamine receptor signaling pathways, we discovered that in addition to being a D1 receptor antagonist, SCH23390 and related compounds inhibit G protein-coupled inwardly rectifying potassium (GIRK) channels. We present evidence that SCH23390 blocks endogenous GIRK currents induced by either somatostatin or D3 dopamine receptors in AtT-20 cells (IC50, 268 nM). The inhibition is receptor-independent because constitutive GIRK currents in Chinese hamster ovary cells expressing only GIRK channels are also blocked by SCH23390. The inhibition of GIRK channels is somewhat selective because members of the closely related Kir2.0 family of inwardly rectifying potassium channels, as well as various endogenous cationic currents present in AtT-20 cells, are not affected. In addition, in current clamp recordings, SCH23390 can depolarize the membrane potential and induce AtT-20 cells to fire action potentials, indicating potential physiological significance of the GIRK channel inhibition. To identify the chemical features that contribute to GIRK channel block, we tested several structurally related compounds [SKF38393, R-(+)-7-chloro-8-hydroxy-1-phenyl-2,3,4,5-tetrahydro-1H-3-benzazepine hydrochloride (nor-methyl-SCH23390), and R-(+)-2,3,4,5-tetrahydro-8-iodo-3-methyl-5-phenyl-1H-3-benzazepin-7-ol hydrochloride (iodo-SCH23390)], and our results indicate that the halide atom is critical for blocking GIRK channels. Taken together, our results suggest that SCH23390 and related compounds might provide the basis for designing novel GIRK channel-selective blockers. Perhaps more importantly, some studies that have exclusively used SCH23390 to probe D1 receptor function or as a diagnostic of D1 receptor involvement may need to be reevaluated in light of these results[3].

However, the doses required to induce a similar response in vivo are greater than 10-fold higher than those required to induce a D1-mediated response. Previous in vivo pharmacological studies with SCH 23390 have shown it to abolish generalized seizures evoked by the chemoconvulsants: pilocarpine and soman. These studies provide evidence of the potential importance of D1-like dopaminergic receptor mechanisms in facilitating the initiation and spread of seizures. The inference from a majority of studies is that the activation of dopamine D1 receptors facilitates seizure activity, whereas activation of D2 receptors may inhibit the development of seizures. SCH 23390 has also been used in studies of other neurological disorders in which the dopamine system has been implicated, such as psychosis and Parkinson's disease. Apart from the study of neurological disorders, SCH 23390 has been extensively used as a tool in the topographical determination of brain D1 receptors in rodents, nonhuman primates, and humans. In summary, SCH 23390 has been a major tool in gaining a better understanding of the role of the dopamine system, more specifically the D1 receptor, in neurological function and dysfunction.[1]

---

DA receptor expression in CD-1 mouse vessels was analyzed by qPCR and immunohistochemistry. Concentration-response curves were established using pressure myography. Pretreatment with SCH23390 (DA1-like receptor antagonist), phentolamine (α -adrenergic receptor antagonist) or indomethacin addressed mechanisms for DA-induced changes. Fenoldopam's effects on postnatal ductus closure were evaluated in vivo.[5]

[1]. SCH 23390: the first selective dopamine D1-like receptor antagonist. CNS Drug Rev. 2001 Winter;7(4):399-414.

[2]. The "selective" dopamine D1 receptor antagonist, SCH23390, is a potent and high efficacy agonist at cloned human serotonin2C receptors. Psychopharmacology (Berl). 2001 Jun;156(1):58-62.

[3]. Classic D1 dopamine receptor antagonist R-(+)-7-chloro-8-hydroxy-3-methyl-1-phenyl-2,3,4,5-tetrahydro-1H-3-benzazepine hydrochloride (SCH23390) directly inhibits G protein-coupledinwardly rectifying potassium channels. Mol Pharmacol. 2002 Jul;62(1):119-26.

[4]. Isosibiricin inhibits microglial activation by targeting the dopamine D1/D2 receptor-dependent NLRP3/caspase-1 inflammasome pathway. Acta Pharmacol Sin. 2020 Feb;41(2):173-180.

[5]. Role of dopamine and selective dopamine receptor agonists on mouse ductus arteriosus tone and responsiveness. Pediatr Res. 2019 Dec 9.

Microglia-mediated neuroinflammation is a crucial risk factor for neurological disorders. Recently, dopamine receptors have been found to be involved in multiple immunopathological processes and considered as valuable therapeutic targets for inflammation-associated neurologic diseases. In this study we investigated the anti-neuroinflammation effect of isosibiricin, a natural coumarin compound isolated from medicinal plant Murraya exotica. We showed that isosibiricin (10-50 μM) dose-dependently inhibited lipopolysaccharide (LPS)-induced BV-2 microglia activation, evidenced by the decreased expression of inflammatory mediators, including nitrite oxide (NO), tumour necrosis factor-α (TNF-α), interleukin-6 (IL-6), interleukin-1β (IL-1β) and interleukin-18 (IL-18). By using transcriptomics coupled with bioinformatics analysis, we revealed that isosibiricin treatment mainly affect dopamine receptor signalling pathway. We further demonstrated that isosibiricin upregulated the expression of dopamine D1/2 receptors in LPS-treated BV-2 cells, resulting in inhibitory effect on nucleotide binding domain-like receptor protein 3 (NLRP3)/caspase-1 inflammasome pathway. Treatment with dopamine D1/2 receptor antagonists SCH 23390 (1 μM) or sultopride (1 μM) could reverse the inhibitory effects of isosibiricin on NLRP3 expression as well as the cleavages of caspase-1 and IL-1β. Collectively, this study demonstrates a promising therapeutic strategy for neuroinflammation by targeting dopamine D1/2 receptors.[4]

---

Background: Indomethacin treatment for patent ductus arteriosus (PDA) is associated with acute kidney injury (AKI). Fenoldopam, a dopamine (DA) DA1-like receptor agonist dilates the renal vasculature and may preserve renal function during indomethacin treatment. However, limited information exists on DA receptor-mediated signaling in the ductus and fenoldopam may prevent ductus closure given its vasodilatory nature. Methods: DA receptor expression in CD-1 mouse vessels was analyzed by qPCR and immunohistochemistry. Concentration-response curves were established using pressure myography. Pretreatment with SCH23390 (DA1-like receptor antagonist), phentolamine (α -adrenergic receptor antagonist) or indomethacin addressed mechanisms for DA-induced changes. Fenoldopam's effects on postnatal ductus closure were evaluated in vivo. Results: DA1 receptors were expressed equally in ductus and aorta. High-dose DA induced modest vasoconstriction under newborn O2 conditions. Phentolamine inhibited DA-induced constriction, while SCH23390 augmented constriction, consistent with a vasodilatory role for DA1 receptors. Despite this, fenoldopam had little effect on ductus tone nor indomethacin- or O2-induced constriction and did not impair postnatal closure in vivo. Conclusion(s): DA receptors are present in the ductus but have limited physiologic effects. DA-induced ductus vasoconstriction is mediated via α-adrenergic pathways. The absence of DA1-mediated impairment of ductus closure supports the study of potential role for fenoldopam during PDA treatment.[5]

C17H19CL2NO

324.24486

323.084

C, 62.97; H, 5.91; Cl, 21.87; N, 4.32; O, 4.93

125941-87-9

SCH-23390 maleate; 87134-87-0; 87075-17-0

11957535

White to light yellow solid powder

414.7ºC at 760 mmHg

204.6ºC

1.81E-07mmHg at 25°C

4.405

2

2

1

21

318

1

OC1=C(Cl)C=C2CCN(C)C[C@H](C3=CC=CC=C3)C2=C1.[H]Cl

OYCAEWMSOPMASE-XFULWGLBSA-N

InChI=1S/C17H18ClNO.ClH/c1-19-8-7-13-9-16(18)17(20)10-14(13)15(11-19)12-5-3-2-4-6-12;/h2-6,9-10,15,20H,7-8,11H2,1H3;1H/t15-;/m1./s1

(5R)-8-chloro-3-methyl-5-phenyl-1,2,4,5-tetrahydro-3-benzazepin-7-ol;hydrochloride

SCH 23390 HCl; SCH-23390; SCH 23390 HYDROCHLORIDE; SCH-23390 hydrochloride; R(+)-SCH-23390 hydrochloride; (R)-(+)-Sch 23390 Hydrochloride; SCH23390 HCl; SCH-23390 (hydrochloride); SCH 23390; SCH23390

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)

DMSO : ≥ 32 mg/mL (~98.69 mM)
H2O : ~28.57 mg/mL (~88.11 mM)

Solubility in Formulation 1: ≥ 2.08 mg/mL (6.42 mM) (saturation unknown) in 10% DMSO + 40% PEG300 +5% Tween-80 + 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 20.8 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.

---

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