NMDA Receptor

In contrast to (-)-HA-966 (IC50=708 μM), (+)-HA-966 suppresses glycine-potentiated NMDA responses on cultured cortical neurons with an IC50=13 μM[2].

(S)-(-)-HA 966 ((-)-HA 966; 3 and 5 mg/kg; ip) inhibits the medial prefrontal cortex and nucleus accumbens from using dopamine when under restriction. Defecation and immobility are two fear-induced responses that are suppressed by (S)-(-)-HA 966[1]. (S)-(-)-HA 966 (3 mg/kg; ip) inhibits the acute motor response that cocaine elicits without changing the process of locomotor sensitization[1]. Although it causes drowsiness, (S)-(-)-HA 966 (5 mg/kg; ip) inhibits acute cocaine-induced locomotion[1].

The antagonist effect of (+/-)-3-amino-1-hydroxypyrrolid-2-one (HA-966) at the N-methyl-D-aspartate (NMDA) receptor occurs through a selective interaction with the glycine modulatory site within the receptor complex. When the enantiomers of (+/-)-HA-966 were resolved, the (R)-(+)-enantiomer was found to be a selective glycine/NMDA receptor antagonist, a property that accounts for its anticonvulsant activity in vivo. In contrast, the (S)-(-)-enantiomer was only weakly active as an NMDA-receptor antagonist, but nevertheless it possessed a marked sedative and muscle relaxant action in vivo. In radioligand binding experiments, (+)-HA-966 inhibited strychnine-insensitive [3H]glycine binding to rat cerebral cortex synaptic membranes with an IC50 of 12.5 microM, whereas (-)-HA-966 had an IC50 value of 339 microM. In electrophysiological experiments, (+)-HA-966 selectively antagonized NMDA receptor responses in rat cortical slices, whereas the (-)-enantiomer was much weaker. On cultured cortical neurones (+)-HA-966 inhibited glycine-potentiated NMDA responses with an IC50 = 13 microM compared with (-)-HA-966, which has an IC50 = 708 microM. In agreement with findings with racemic HA-966, even high concentrations of (+)-HA-966 did not completely inhibit NMDA responses, suggesting that (+)-HA-966 is a low-efficacy partial agonist. (+)-HA-966 produced parallel shifts to the right of the glycine concentration curve for potentiation of NMDA responses, resulting in an estimated pKb = 5.6. In mice, (+)-HA-966 antagonized sound and N-methyl-DL-aspartic acid (NMDLA)-induced seizures with ED50 values of 52.6 mg/kg of body weight (i.p.) and 900 mg/kg (i.v.), respectively. The coadministration of D-serine dose-dependently (10-100 micrograms into the cerebral ventricles per mouse) antagonized the anticonvulsant effect of a submaximal dose of (+)-HA-966 (100 micrograms administered directly into the cerebral ventricles) against NMDLA-induced seizures. The sedative/ataxic effect of racemic HA-966 was mainly attributable to the (-)-enantiomer, which was greater than 25-fold more potent than the (+)-enantiomer. It is suggested that, as in the case of the sedative gamma-butyrolactone, disruption of striatal dopaminergic mechanisms may be responsible for this action[2].

This report investigates the effect of the negative enantiomer of 1-hydroxy-3-aminopyrrolidone-2 (HA-966) on behavioral and biochemical changes elicited by pharmacological or experimental paradigms which activate mesocorticolimbic dopaminergic neurotransmission. Several paradigms were used, including cocaine sensitization and two stressors: restraint for 30 min and an aversive conditioning model. (S)-(-)-HA-966 (3 and 5 mg/kg i.p.) prevented restraint stress-induced dopamine utilization in both the medial prefrontal cortex and nucleus accumbens, in contrast to the positive enantiomer. Conditioned fear increased dopamine metabolism in both the core and shell subdivisions of the nucleus accumbens, an effect blocked by (S)-(-)-HA-966. The conditioned stress-induced increase in dopamine metabolism in the medial prefrontal cortex was also blocked by (S)-(-)-HA-966. In addition, (S)-(-)-HA-966 suppressed fear-induced behaviors: immobility and defecation. In other studies, (S)-(-)-HA-966 (3 mg/kg i.p.) prevented locomotor sensitization without altering the acute motoric response elicited by cocaine. The highest dose of (S)-(-)-HA-966 (5 mg/kg i.p.) blocked acute cocaine-induced locomotion but resulted in sedation. In addition, the highest dose of (S)-(-)-HA-966 tested suppressed weight gain in control rats, unlike its enantiomer, (R)-(+)-HA-966. Because (S)-(-)-HA-966 has been proposed to act at the gamma-aminobutyric acid (GABA)B receptor, we examined the ability of (S)-(-) and (R)-(+)-HA-966 to displace [3H]-(-)-baclofen from cortical membranes to assess GABAB receptor binding. Neither enantiomer significantly altered [3H]-(-)-baclofen binding at relevant concentrations, indicating the actions of (S)-(-)-HA-966 reported here are the results of a mechanism apparently independent of the baclofen binding site on the GABAB receptor[1].

[1]. (S)-(-)-HA-966, a gamma-hydroxybutyrate-like agent, prevents enhanced mesocorticolimbic dopamine metabolism and behavioral correlates of restraint stress, conditioned fear and cocaine sensitization. J Pharmacol Exp Ther. 1997 Nov;283(2):712-21.

[2]. Enantiomers of HA-966 (3-amino-1-hydroxypyrrolid-2-one) exhibit distinct central nervous system effects: (+)-HA-966 is a selective glycine/N-methyl-D-aspartate receptor antagonist, but (-)-HA-966 is a potent gamma-butyrolactone-like sedative. Proc Natl Acad Sci U S A. 1990 Jan;87(1):347-51.

C4H8N2O2

117.12646

116.059

111821-58-0

183351

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

1.436 g/cm3

258.6ºC at 760 mmHg

110.2ºC

-1.5

2

3

0

8

115

1

[NH3+][C@H]1CCN(O)C1=O

HCKUBNLZMKAEIN-VKHMYHEASA-N

InChI=1S/C4H8N2O2/c5-3-1-2-6(8)4(3)7/h3,8H,1-2,5H2/t3-/m0/s1

(3S)-3-amino-1-hydroxypyrrolidin-2-one

111821-58-0; (S)-(-)-HA-966; (S)-(-)-3-Amino-1-hydroxypyrrolidin-2-one; (3S)-3-amino-1-hydroxypyrrolidin-2-one; (S)-(-)-HA 966; HA-966, (S)-; (-)-HA 966; 2-Pyrrolidinone, 3-amino-1-hydroxy-, (S)-;

2934.99.9001

Powder      -20°C    3 years

                     4°C     2 years

In solvent   -80°C    6 months

                  -20°C    1 month

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

May dissolve in DMSO (in most cases), if not, try other solvents such as H2O, Ethanol, or DMF with a minute amount of products to avoid loss of samples

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.)