mGluR1a ( IC50 = 7.8 μM ); mGluR2 ( IC50 = 21 nM ); mGluR3 ( IC50 = 14 nM ); mGluR4 ( IC50 = 22 μM ); mGluR5a ( IC50 = 8.2 μM ); mGluR7 ( IC50 = 990 nM ); mGluR8 ( IC50 = 170 nM )

Effects of LY341495 on Akt and Wnt pathway proteins [2]
The mGlu2/3 antagonist LY341495 was used to examine the effects of blocking the mGlu2/3 on Akt and Wnt pathway proteins. Repeated treatment with 3.0 mg/kg of LY341495 decreased Dvl-2, pGSK-3α/β and β-catenin protein levels but Dvl-1, Dvl-3 and GSK-3α/β were unaffected in both the PFC and STR (Fig. 3a and b). In addition, to changes in the Wnt proteins, a reduction in pAkt Ser473 but not in total Akt or pAkt Thr308 were observed in the PFC and STR (Fig. 3c and d). A lower dose of repeated LY341495 (1.0 mg/kg) was also used and had no effect on Akt or Wnt pathway proteins tested in the PFC or STR (data not shown). Finally, changes in Akt and Wnt pathway proteins were assessed following acute administration of LY341495. Decreases in pGSK-3α/β (Fig. 4a and b) and pAkt Ser473 (Fig. 4c and d) were observed in the PFC and STR following acute administration of LY341495 (3.0 mg/kg). Therefore, acute administration of LY341495 decreased pAkt and pGSK-3 levels but repeated treatment (3.0 mg/kg) is needed to reduce β-catenin levels. Furthermore, LY341495 had the generally the opposite effect following acute and chronic administration compared to mGlu2/3 agonist, LY379268.

LY341495 (0.3, 1 and 3 mg/kg, ip) exhibits lower levels of insight into the state [1]. LY341495 (3.0 mg/kg) reduced Dvl-2, pGSK-3α/β and β-catenin protein levels, but Dvl-1, Dvl-3 and GSK-3α/β were not activated in PFC and STR. Compared with the mGlu2/3 stimulant LY379268, LY341495 generally produces just the right effect after fast and fast[2]. c-Fos expression induced by LY341495 (3 mg/kg, i.p., 2.5 hours) was not altered in either KO brain. In mGluR3-KO, LY341495 has little activity in the central extended amygdala [central amygdala] nucleus, nucleus of cancellation (CeL) and bed nucleus of stria terminalis, dorsal nucleus (BSTLD) [3].

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Experimental evidence suggests that metabotropic glutamate 2/3 (mGlu2/3) receptor antagonists affect cognitive function, although contradictory findings have been reported. To clarify the role of mGlu2/3 receptor antagonists in one aspect of cognition, the present study investigated the effects of a broad range of doses of the mGlu2/3 receptor antagonist LY341495 on post-training recognition memory components (storage and/or retrieval) in rats. The efficacy of LY341495 in antagonizing the extinction of recognition memory was also investigated. The novel object recognition test was used as the memory test. The highest LY341495 doses administered (0.3, 1, and 3 mg/kg) disrupted performance in this recognition memory procedure in rats at all delay conditions tested, whereas administration of lower doses (0.05 and 0.1 mg/kg) did not impair recognition memory. Moreover, administration of the low LY341495 doses (0.05 and 0.1 mg/kg) counteracted the extinction of recognition memory. The present results indicate that administration of the mGlu2/3 receptor antagonist LY341495 can either impair or enhance recognition memory in rats, depending on the dose of the compound and delay period used. Thus, together with previously reported findings, the present data suggest complex effects of this compound on cognitive function, particularly recognition memory.[1]

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LY341495 is a metabotropic glutamate receptor (mGluR) antagonist showing selectivity to mGluR2/3 but having measurable antagonist efficacy across all mGluR subtypes at 10-1000 fold higher concentrations. In vivo in rodents it increases locomotor activity and wakefulness, enhances cognition and modulates emotions. It also induces widespread neuronal activation measured as c-Fos expression. To further investigate the receptor subtypes through which LY341495 might act in vivo we analyzed how its effects are altered in mGluR2-knockout (KO) and mGluR3-KO brains. In most regions, LY341495 (3 mg/kg, i.p., 2.5 h) -induced c-Fos expression was not altered in either KO brain. However, in mGluR3-KO mice, LY341495 was almost inactive in the central extended amygdala [central nucleus of the amygdala, lateral (CeL) and bed nucleus of the stria terminalis, laterodorsal (BSTLD)], suggesting that acute blockade of mGluR3 is activating these neurons in wildtype brain. In the ventrolateral nucleus of the thalamus (VL), LY341495 produced a significantly enhanced response in mGluR3-KO mice and attenuated response in mGluR2-KO mice. We also analyzed locomotion in familiar environment and found that locomotor activity was dose-dependently increased by LY341495 (1-30 mg/kg, i.p.) regardless of the genotype. In unfamiliar environment, both KO strains showed enhanced sensitivity to LY341495 in reducing locomotor habituation. Together our results indicate that certain effects of LY341495 may not be mediated by a blockade of either mGluR2 or mGluR3, but may involve other mGluR subtypes. Alternatively, functions of mGluR2 and mGluR3 may be redundant, resulting similar effects irrespective the receptor subtype being antagonized in vivo by LY341495. [3]

The in vitro pharmacology of a structurally novel compound, LY341495, was investigated at human recombinant metabotropic glutamate (mGlu) receptor subtypes expressed in non-neuronal (RGT, rat glutamate transporter) cells. LY341495 was a nanomolar potent antagonist of 1S,3R-1-aminocyclopentane-1,3-dicarboxylic acid (ACPD)-induced inhibition of forskolin-stimulated cAMP formation at mGlu2 and mGlu3 receptors (respective IC50S of 0.021 and 0.014 microM). At group I mGlu receptor expressing cells, LY341495 was micromolar potent in antagonizing quisqualate-induced phosphoinositide (PI) hydrolysis, with IC50 values of 7.8 and 8.2 microM for mGlu1a and mGlu5a receptors, respectively. Among the human group III mGlu receptors, the most potent inhibition of L-2-amino-4-phosphonobutyric acid (L-AP4) responses was seen for LY341495 at mGlu8, with an IC50 of 0.17 microM. LY341495 was less potent at mGlu7 (IC50 = 0.99 microM) and least potent at mGlu4 (IC50 = 22 microM). Binding studies in rat brain membranes also demonstrated nanomolar potent group II mGlu receptor affinity for LY341495, with no appreciable displacement of ionotropic glutamate receptor ligand binding. Thus, LY341495 has a unique range of selectivity across the mGlu receptor subtypes with a potency order of mGlu3 > or = mGlu2 > mGlu8 > mGlu7 >> mGlu1a = mGlu5a > mGlu4. In particular, LY341495 is the most potent antagonist yet reported at mGlu2, 3 and 8 receptors. Thus, it represents a novel pharmacological agent for elucidating the function of mGlu receptors in experimental systems [5].

Western blotting [2]
Protein isolation, quantification and western blotting were performed as previously described for the PFC and STR (Alimohamad et al. 2005a). Densitometry values were obtained from X-ray film using a grey scale calibrated scanner and Kodak Molecular Imaging software. Densitometry values were corrected for α-tubulin and expressed as a percentage of control. Data were analyzed for statistical significance using a Student’s t-test.

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Co-immunoprecipitations [2]
Protein was isolated from the PFC of drug naïve rats or rats treated with LY379268 (3 mg/kg, i.p.) using a non-denaturing lysis buffer with the addition of protease and phosphatase inhibitors (n = 6 rats/experiment). Immunoprecipitations (IPs) were performed using the ExactCruz system, 500 μg of protein and antibodies for the mGlu2/3 (4 μg/IP) or Dvl-2 (4 μg/IP) as outlined previously (Sutton et al. 2007). Negative controls were performed using a non-specific IgG from the same species in place of the IP antibody. The IP samples were subjected to western blotting and probed for the protein of interest; Dvl-2 (1 : 100), Dvl-3 (Santa Cruz Biotechnology; 1 : 100), GSK-3 (1 : 300) Akt (1 : 1250).

Six experimental groups (each with ten rats) are created by randomly assigning the rats: vehicle and 0.05, 0.1, 0.3, 1, and 3 mg/kg LY341475. The LY341495 doses are selected on the basis of results from previous Published studies that evaluated the effects of this compound on cognition. Training: Two 2-minute trials were given to the rats during the training session. Right after T1, the animals are given either LY341495 or the vehicle. Given that untreated control rats in these experiments still have intact recognition memory, an ITI of one hour is employed with a 2-min trial duration.

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Locomotor activity [2]
Horizontal locomotor activity was recorded from rats treated with LY341495 (1.0 and 3.0 mg/kg, i.p.) or an appropriate vehicle following a single injection or following five consecutive daily injections (n = 12 rats/treatment). In a separate set of experiments, rats were treated once or daily for five consecutive days with LY341495 (3.0 mg/kg, i.p.) or vehicle followed 5 min later by the administration of the GSK-3 inhibitor, SB216763 (3.0 mg/kg, i.p.) or vehicle (n = 8 rats/treatment). The dose of SB216763 was selected based on previous studies showing that treatment attenuated hyperlocomotion in DAT-KO mice at 3.0 mg/kg (Beaulieu et al. 2004). Horizontal locomotor activity was recorded on day 1 and day 5 and all experiments were conducted in the light phase between 9:00 and 13:00 hours. Horizontal locomotor activity was recorded using Med Associates activity monitor chambers and software for 60 min. Data was analyzed using a one-way anova or two-way anova followed by the Newman-Keuls post hoc test.

[1]. The metabotropic glutamate 2/3 receptor antagonist LY341495 differentially affects recognition memory in rats. Behav Brain Res. 2012 May 1;230(2):374-9.

[2]. Regulation of Akt and Wnt signaling by the group II metabotropic glutamate receptor antagonist LY341495 and agonist LY379268.J Neurochem. 2011 Jun;117(6):973-83.

[3]. Use of MGLUR2 and MGLUR3 knockout mice to explore in vivo receptor specificity of the MGLUR2/3 selective antagonist LY341495. Neuropharmacology. 2009 Aug;57(2):172-82. Epub 2009 May 27.

[4]. N-acetyl-cysteine attenuates neuropathic pain by suppressing matrix metalloproteinases. Pain. 2016 Aug;157(8):1711-23.

[5]. LY341495 Is a Nanomolar Potent and Selective Antagonist of Group II Metabotropic Glutamate Receptors.Neuropharmacology. 1998;37(1):1-12.

(1S,2S)-2-[(1S)-1-amino-1-carboxy-2-(9H-xanthen-9-yl)ethyl]-1-cyclopropanecarboxylic acid is a member of xanthenes.

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Metabotropic glutamate receptors 2/3 (mGlu(2/3)) have been implicated in schizophrenia and as a novel treatment target for schizophrenia. The current study examined whether mGlu(2/3) regulates Akt (protein kinase B) and Wnt (Wingless/Int-1) signaling, two cascades associated with schizophrenia and modified by antipsychotics. Western blotting revealed increases in phosphorylated Akt (pAkt) and phosphorylated glycogen synthase kinase-3 (pGSK-3) following acute and repeated treatment of LY379268 (mGlu(2/3) agonist), whereas increases in dishevelled-2 (Dvl-2), dishevelled-3 (Dvl-3), GSK-3 and β-catenin were only observed following repeated treatment. LY341495 (mGlu(2/3) antagonist) induced the opposite response compared with LY379268. Co-immunoprecipitation experiments showed an association between the mGlu(2/3) complex and Dvl-2 providing a possible mechanism to explain how the mGlu(2/3) can mediate changes in Wnt signaling. However, there was no association between the mGlu(2/3) complex and Akt suggesting that changes in Akt signaling following LY341495 and LY379268 treatments may not be directly mediated by the mGlu(2/3) . Finally, an increase in locomotor activity induced by LY341495 treatment correlated with increased pAkt and pGSK-3 levels and was attenuated by the administration of the GSK-3 inhibitor, SB216763. Overall, the results suggest that mGlu(2/3) regulates Akt and Wnt signaling and LY379268 treatment has overlapping effects with D(2) dopamine receptor antagonists (antipsychotic drugs).[2]

C20H19NO5

353.36856

353.126

C, 67.98; H, 5.42; N, 3.96; O, 22.64

201943-63-7

(Rac)-LY341495

9819927

White to off-white solid powder

1.4±0.1 g/cm3

580.8±40.0 °C at 760 mmHg

305.1±27.3 °C

0.0±1.7 mmHg at 25°C

1.669

2.53

3

6

5

26

559

3

O=C(O)[C@@H]1[C@H](C1)[C@@](N)(CC2C3=C(C=CC=C3)OC4=C2C=CC=C4)C(O)=O

VLZBRVJVCCNPRJ-KPHUOKFYSA-N

InChI=1S/C20H19NO5/c21-20(19(24)25,15-9-13(15)18(22)23)10-14-11-5-1-3-7-16(11)26-17-8-4-2-6-12(14)17/h1-8,13-15H,9-10,21H2,(H,22,23)(H,24,25)/t13-,15-,20-/m0/s1

(1S,2S)-2-[(1S)-1-amino-1-carboxy-2-(9H-xanthen-9-yl)ethyl]cyclopropane-1-carboxylic acid

LY 341495; LY-341495; 201943-63-7; (2S)-2-AMINO-2-[(1S,2S)-2-CARBOXYCYCLOPROP-1-YL]-3-(XANTH-9-YL) PROPANOIC ACID; 2-[(1s,2s)-2-Carboxycyclopropyl]-3-(9h-Xanthen-9-Yl)-D-Alanine; (1S,2S)-2-[(1S)-1-amino-1-carboxy-2-(9H-xanthen-9-yl)ethyl]cyclopropane-1-carboxylic acid; 9H-Xanthene-9-propanoic acid, alpha-amino-alpha-[(1S,2S)-2-carboxycyclopropyl]-, (alphaS)-; LY341495

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)

DMSO: ~6 mg/mL (~17 mM)

Solubility in Formulation 1: ≥ 0.6 mg/mL (1.70 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 6.0 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.)