5-HT2B Receptor (pKi = 7.5); 5-HT2C Receptor (pKi = 6.9); 5-HT2A Receptor (pKi = 5.2)

The ethanol-induced rise in the frequency of miniature inhibitory postsynaptic currents (mIPSCs) is eliminated by SB200646A (4 μM), whereas the basal mIPSC frequency remains unaffected[1].

The treatment of male albino Sprague-Dawley rats with SB-200646A (20 mg/kg; intravenous injection; daily; for 21 days) dramatically reduces the number of spontaneously activated dopaminergic neurons in the ventral tegmental area (VTA)[1]. In spontaneously activated VTA dopaminergic neurons, the intravenous administration of 4–16 mg/kg of SB-200646A greatly enhances the firing rate and percentage of events as bursts, whereas in substantia nigra pars compacta (SNC) dopaminergic neurons, it significantly increases the percentage of events as bursts[1].

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1. SB 200646A, N-(1-methyl-5-indolyl)-N'-(3-pyridyl) urea hydrochloride, the first reported selective 5-HT2C/2B over 5-HT2A receptor antagonist, (pK1 rat 5-HT2C receptor 6.9, pA2 rat 5-HT2B receptor 7.5, pK1 rat 5-HT2A receptor 5.2) dose-dependently blocked a putative rat model of 5-HT2C receptor activation; 1-(3-chlorophenyl)piperazine (mCPP, 5 mg kg-1, i.p. 20 min pretest)-induced hypolocomotion (estimated ID50 19.2 mg kg-1, p.o.). 2. SB 200646A also blocked another putative in vivo model of 5-HT2C receptor function; mCPP (5 mg kg-1, i.p. 20 min pretest)-induced hypophagia in 23 h food-deprived rats (estimated ID50 18.3 mg kg-1, p.o.). 3. SB 200646A did not antagonize 1-(2,5-dimethoxy-4-iodophenyl)-2-aminopropane (DOI)-induced head shakes in rats at doses up to 200 mg kg-1, p.o., an effect thought to be mediated by 5-HT2A receptors for which SB 200646A has its next highest affinity (50 fold less) after the 5-HT2C and 5-HT2B sites. 4. SB 200646A (20, 40 mg kg-1, p.o., 1 h pretest) also reversed mCPP (0.5 mg kg-1, i.p., 30 min pretest)-induced anxiety in the social interaction test, under low light familiar conditions. 5. When given alone, under high light unfamiliar conditions, SB 200646A (2-40 mg kg-1, p.o.) increased active social interaction without affecting locomotor activity in the rat social interaction test. This is consistent with an anxiolytic action of SB 200646A. 6. These results indicate that SB 200646A has in vivo efficacy and that 5-HT2C or 5-HT2B receptors are indeed likely to mediate mCPP-induced hypolocomotion, hypophagia and anxiogenesis. They also suggest that 5-HT2C,2B receptor blockade induces anxiolysis[2].

Electrophysiological Recordings of VTA-DA Neurons. Individual slices were transferred to a recording chamber and perfused with oxygenated aCSF (30–32°C) at a flow rate of ∼2 ml/min. Recording aCSF was as described above except it contained 0.9 mM MgSO4 and 2 mM CaCl2. Cells were visualized using IR-DIC optics on an Olympus BX-50WI microscope. The VTA was identified as being medial to the medial terminal nucleus of the accessory optic tract and rostral to the oculomotor nerve and the medial lemniscus. The majority of recordings were conducted in the lateral VTA, just medial to the medial terminal nucleus of the accessory optic tract. Whole-cell voltage-clamp recordings were used for all experiments; putative DA neurons were identified by the presence of a large hyperpolarization-activated cationic current (>200 pA) that was measured immediately after break-in by application of a 1.5-s hyperpolarizing step from -60 to -110 mV (Johnson and North, 1992b). Recording electrodes were made from thin-walled borosilicate glass (TW 150F-4; WPI, Sarasota, FL; 1.5–2.5 MΩ) and contained 135 mM KCl, 12 mM NaCl, 0.5 mM EGTA, 10 mM HEPES, 2 mM Mg-ATP, and 0.3 mM Tris-GTP, pH 7.3, with KOH. Data were collected by an Axon Instruments model 200B amplifier filtered at 1 kHz and digitized at 10 to 20 kHz with a Digidata interface using pClamp version 9.2 and 10.2. GABAergic mIPSCs were pharmacologically isolated with kynurenic acid (1 mM) to inhibit α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid- and N-methyl-d-aspartate receptor-mediated currents. Tetrodotoxin (TTX; 0.5 μM) and eticlopride (250 nM) were included to block Na+ currents and D2 receptor-mediated currents, respectively. Under these conditions, mIPSCs were inward at a holding potential of -60 mV, and in an initial set of experiments, their identity as GABAeric events was verified by testing for block with picrotoxin or bicuculline (data not shown). After break-in and a stable 10-min baseline (control) recording, drugs were bath-applied through the aCSF perfusion line, and a continuous 10- to 15-min recording epoch was used to detect changes in mIPSC frequency and amplitude. A 4-min drug wash-on preceded the start of data collection in each treatment condition, and a 12-min washout period followed drug application. The last half (6 min) of the washout period was used in our data analysis. The number of neurons used per each treatment condition is represented as n, with only one neuron used per slice[3].

Animal/Disease Models: Male albino SD (Sprague-Dawley) rats (200-225 g at the beginning of treatment and 300-350 g at the time of the experiment)[1]
Doses: 20 mg/kg
Route of Administration: intravenous (iv) injection; daily; for 21 days
Experimental Results: Dramatically diminished the number of spontaneously active ventral tegmental area (VTA) dopaminergic neurons.

[1]. Blackburn TP, et al. The acute and chronic administration of the 5-HT(2B/2C) receptor antagonist SB-200646A significantly alters the activity of spontaneously active midbrain dopamine neurons in the rat: An in vivo extracellular single cell study. Synapse
[2]. Kennett GA, et al. In vivo properties of SB 200646A, a 5-HT2C/2B receptor antagonist. Br J Pharmacol. 1994 Mar;111(3):797-802.
[3]. Theile JW, et al. Role of 5-hydroxytryptamine2C receptors in Ca2+-dependent ethanol potentiation of GABA release onto ventral tegmental area dopamine neurons. J Pharmacol Exp Ther. 2009 May;329(2):625-33.

This study examined the effect of the acute and chronic administration of the 5-HT(2B/2C) receptor antagonist N-(1-methyl-5-indolyl)-N'-(3-pyridyl) urea hydrochloride (SB-200646A) on the activity of spontaneously active DA cells in the substantia nigra pars compacta (SNC) and ventral tegmental area (VTA) in anesthetized, male Sprague-Dawley rats. This was accomplished using in vivo extracellular single cell recording. The i.v. administration of 4-16 mg/kg of SB-200646A significantly increased the firing rate and % events as bursts in spontaneously active VTA DA neurons and significantly increased the % events as burst in SNC DA neurons. The acute i.p. administration of 20 and 40 mg/kg of SB-200646A significantly increased the number of spontaneously active VTA DA neurons when compared with vehicle-treated controls. The acute administration of 10 mg/kg of SB-200646A significantly increased the coefficient of variation in spontaneously active SNC and DA neurons when compared with vehicle-treated controls. However, the acute i.p. administration of 20 mg/kg of SB-200646A significantly decreased the degree of bursting of VTA DA neurons. Similary, chronic i.p. administration of 10 mg/kg of SB-200646 did not significantly alter firing, whereas chronic administration of 20 mg/kg of SB-200646A or 20 mg/kg of clozapine significantly decreased the number of spontaneously active VTA DA neurons when compared with vehicle-treated controls. The SB-200646A-induced decrease in the number of spontaneously active VTA DA neurons was reversed by the i.v. administration of (+)-apomorphine or (-)-baclofen. The chronic i.p. administration of either 10 or 20 mg/kg of SB-200646A did not significantly alter the firing pattern of spontaneously active SNC DA neurons. However, the chronic administration of 20 mg/kg of SB-200646A significantly increased the degree of bursting in VTA DA neurons when compared with vehicle. Overall, the acute and chronic administration of SB-200646A produces in vivo electrophysiological effects, resembling that of atypical antipsychotic drugs.[1]

C15H15CLN4O

302.76

302.093

C, 59.51; H, 4.99; Cl, 11.71; N, 18.51; O, 5.28

143797-62-0

SB-200646; 143797-63-1

5311422

Typically exists as Off-white to light yellow solid at room temperature

3

2

2

21

349

0

Cl.C1C=CC(NC(NC2C=CC3N(C=CC=3C=2)C)=O)=CN=1

IGRYPUQJEDJLHC-UHFFFAOYSA-N

InChI=1S/C15H14N4O.ClH/c1-19-8-6-11-9-12(4-5-14(11)19)17-15(20)18-13-3-2-7-16-10-13;/h2-10H,1H3,(H2,17,18,20);1H

1-(1-methylindol-5-yl)-3-pyridin-3-ylurea;hydrochloride

SB 200646 hydrochloride; 143797-62-0; SB-200646A; SB 200646 HCl; 1-(1-methylindol-5-yl)-3-pyridin-3-ylurea;hydrochloride; SB-200646 hydrochloride; SB200646; 3-(1-METHYLINDOL-5-YL)-1-(PYRIDIN-3-YL)UREA HYDROCHLORIDE;

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: 250 mg/mL (825.74 mM)

Note: Listed below are some common formulations that may be used to formulate products with low water solubility (e.g. < 1 mg/mL), you may test these formulations using a minute amount of products to avoid loss of samples.

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Injection Formulation 1: DMSO : Tween 80： Saline = 10 : 5 : 85 (i.e. 100 μL DMSO stock solution → 50 μL Tween 80 → 850 μL Saline)
*Preparation of saline: Dissolve 0.9 g of sodium chloride in 100 mL ddH ₂ O to obtain a clear solution.
Injection Formulation 2: DMSO : PEG300 ：Tween 80 : Saline = 10 : 40 : 5 : 45 (i.e. 100 μL DMSO → 400 μLPEG300 → 50 μL Tween 80 → 450 μL Saline)
Injection Formulation 3: DMSO : Corn oil = 10 : 90 (i.e. 100 μL DMSO → 900 μL Corn oil)
Example: Take the Injection Formulation 3 (DMSO : Corn oil = 10 : 90) as an example, if 1 mL of 2.5 mg/mL working solution is to be prepared, you can take 100 μL 25 mg/mL DMSO stock solution and add to 900 μL corn oil, mix well to obtain a clear or suspension solution (2.5 mg/mL, ready for use in animals).

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Injection Formulation 4: DMSO : 20% SBE-β-CD in saline = 10 : 90 [i.e. 100 μL DMSO → 900 μL (20% SBE-β-CD in saline)]
*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.
Injection Formulation 5: 2-Hydroxypropyl-β-cyclodextrin : Saline = 50 : 50 (i.e. 500 μL 2-Hydroxypropyl-β-cyclodextrin → 500 μL Saline)
Injection Formulation 6: DMSO : PEG300 : castor oil : Saline = 5 : 10 : 20 : 65 (i.e. 50 μL DMSO → 100 μLPEG300 → 200 μL castor oil → 650 μL Saline)
Injection Formulation 7: Ethanol : Cremophor : Saline = 10： 10 : 80 (i.e. 100 μL Ethanol → 100 μL Cremophor → 800 μL Saline)
Injection Formulation 8: Dissolve in Cremophor/Ethanol (50 : 50), then diluted by Saline
Injection Formulation 9: EtOH : Corn oil = 10 : 90 (i.e. 100 μL EtOH → 900 μL Corn oil)
Injection Formulation 10: EtOH : PEG300：Tween 80 : Saline = 10 : 40 : 5 : 45 (i.e. 100 μL EtOH → 400 μLPEG300 → 50 μL Tween 80 → 450 μL Saline)

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Oral Formulation 1: Suspend in 0.5% CMC Na (carboxymethylcellulose sodium)
Oral Formulation 2: Suspend in 0.5% Carboxymethyl cellulose
Example: Take the Oral Formulation 1 (Suspend in 0.5% CMC Na) as an example, if 100 mL of 2.5 mg/mL working solution is to be prepared, you can first prepare 0.5% CMC Na solution by measuring 0.5 g CMC Na and dissolve it in 100 mL ddH2O to obtain a clear solution; then add 250 mg of the product to 100 mL 0.5% CMC Na solution, to make the suspension solution (2.5 mg/mL, ready for use in animals).

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Oral Formulation 3: Dissolved in PEG400
Oral Formulation 4: Suspend in 0.2% Carboxymethyl cellulose
Oral Formulation 5: Dissolve in 0.25% Tween 80 and 0.5% Carboxymethyl cellulose
Oral Formulation 6: Mixing with food powders

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Note: Please be aware that the above formulations are for reference only. InvivoChem strongly recommends customers to read literature methods/protocols carefully before determining which formulation you should use for in vivo studies, as different compounds have different solubility properties and have to be formulated differently.

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