SSTR3 SSTR5

For sst1, sst4, and sst2, BIM 23056 TFA has Ki values of 142, 16.6, and >1000, respectively[1].
Recent reports (Raynor et al) have claimed the identification of potent somatostatin (SST) agonists exhibiting binding affinities of 1-2 pM and up to 30,000 fold binding selectivity for several of the 5 cloned sstr subtypes. These conclusions, however, are based on binding comparisons of sstr subtypes from different species expressed in different cell lines and studied with different radioligands. To eliminate the effect of species and/or methodological variations, we have investigated agonist selectivity of 32 synthetic SST analogs for all 5 hsstrs stably expressed in CHO-K1 cells under identical binding conditions. We show that hsstr2, 3, 5 react potently with hexapeptide as well as cyclic and linear octapeptide analogs and belong to a similar sstr subclass. hsstr1 and 4 react poorly with these analogs and belong to a separate subclass. The present generation of SST analogs exhibit a modest-50 fold increase in binding potency compared to SST-14 for 2 subtypes (hsstr2, 3), and relative selectivity for only 1 subtype (hsstr2) which is at best only 35 fold. The potency and degree of selectivity of these analogs is several orders of magnitude less than that reported earlier and suggests the need for caution in using these compounds as putative superagonists or subtype selective compounds for any of the individual sstrs.[1]

1. Somatostatin (SRIF) causes a concentration-dependent inhibition of neurotransmission in guinea-pig ileum and vas deferens as well as negative inotropy in guinea-pig isolated right atrium. The SRIF receptors mediating these effects have now been further characterized by use of the peptides BIM-23027, BIM-23056 and L-362855, reported as selective for the recombinant SRIF receptor types, sst2, sst3 and sst5, respectively. 2. BIM-23027 was a highly potent agonist at causing an inhibition of neurotransmission in the guinea-pig ileum (EC50 value 1.9 nM), being about 3 times more potent than SRIF (EC50 value 6.8 nM). In contrast, in both guinea-pig vas deferens and right atrial preparations, BIM-23027 was a relatively weak agonist being at least 30-100 times weaker than SRIF. In guinea-pig atria, BIM-23027 (3 microM) antagonized the negative inotropic action of SRIF28 (apparent pKB = 5.9 +/- 0.1) but had no effect on the negative inotropic action of cyclohexyladenosine. 3. The inhibitory effect of BIM-23027 in the guinea-pig ileum was readily desensitized. Prior exposure to BIM-23027 (0.3 microM) markedly attenuated the inhibitory effect of SRIF but had no effect on the inhibitory action of clonidine suggesting that BIM-23027 and SRIF act via a common receptor mechanism. 4. L-362855 caused a concentration-dependent inhibition of neurotransmission in both the guinea-pig ileum and vas deferens as well as causing negative inotropy in the guinea-pig atrium but was at least 30-100 times weaker than SRIF. In guinea-pig isolated atria, L-362855 (3 microM) did not antagonize the negative inotropic action of SRIF28. 5. BIM-23056 in concentrations up to 1 microM was inactive as an agonist in guinea-pig isolated ileum, vas deferens and atrium and did not antagonize the inhibitory actions of SRIF in any of these preparations.6. The results from this study support our previous contention that the sst2 receptor type mediates inhibition of neurotransmission by SRIF in the guinea-pig ileum. The SRIF receptor type mediating inhibition of neurotransmission in the guinea-pig vas deferens appears different, but similar, to that mediating negative inotropy in the atrium. However the characteristics of these latter receptors appear different from that of the recombinant sst2, sst3 and sst5 receptors for SRIF described for rat and man.

[1]. Subtype selectivity of peptide analogs for all five cloned human somatostatin receptors (hsstr 1-5). Endocrinology. 1994 Dec;135(6):2814-7.

[2]. Further evidence from functional studies for somatostatin receptor heterogeneity in guinea-pig isolated ileum, vas deferens and right atrium. Br J Pharmacol. 1995 Jul;115(6):975-80.

Five different receptor ligands were investigated in this study, BIM-23027 (sst2 receptor agonist; Bell & Reisine, 1993), CYN-154806 (sst2 receptor antagonist; Bass et al., 1996), NNC 26-9100 (sst4 receptor agonist; Ankersen et al., 1998), L-362,855 (sst2,5 receptor agonist; Williams et al., 1997) and BIM-23056 (sst5 receptor antagonist; Wilkinson et al., 1997); these were all applied via the microdialysis probes (retrodialysis). Dialysate samples were collected initially for 90 min to establish baseline values. All of the compounds were dissolved in Krebs-Ringer (containing neostigmine) and retrodialysed for a 15 min period 90 min after the commencement of sampling and once again 135 min later. Between challenges the perfusing solution was changed back to Krebs-Ringer. In experiments using NNC 26-9100, L-362,855 and BIM-23056, three concentrations of each compound were tested (1, 50 and 1000 nm).Br J Pharmacol. 1999 Nov; 128(6): 1346–1352.

C73H82F3N11O11

1346.49

1346.49

1426173-61-6

BIM-23056;150155-61-6

D-phenylalanyl-L-phenylalanyl-L-tyrosyl-D-tryptophyl-L-lysyl-L-valyl-L-phenylalanyl-3-(2-naphthyl)-D-alaninamide TFA

FFYWKVF-{D-2-Nal}-NH2

Typically exists as solid at room temperature

9.6

BIM 23056 TFA; D-Alaninamide, D-phenylalanyl-L-phenylalanyl-L-tyrosyl-D-tryptophyl-L-lysyl-L-valyl-L-phenylalanyl-3-(2-naphthalenyl)-; (2S)-6-Amino-N-[(2S)-1-[[(2S)-1-[[(2R)-1-amino-3-naphthalen-2-yl-1-oxopropan-2-yl]amino]-1-oxo-3-phenylpropan-2-yl]amino]-3-methyl-1-oxobutan-2-yl]-2-[[(2R)-2-[[(2S)-2-[[(2S)-2-[[(2R)-2-amino-3-phenylpropanoyl]amino]-3-phenylpropanoyl]amino]-3-(4-hydroxyphenyl)propanoyl]amino]-3-(1H-indol-3-yl)propanoyl]amino]hexanamide; FFYWKVFA; D-Phe-Phe-Tyr-D-Trp-Lys-Val-Phe-D-Nal-NH2; CHEMBL410596; SCHEMBL12912367;

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.)