| Field | Specification |
|---|---|
| CAS no. | |
| Applications | |
| Molecular weight | |
| Molecular formula | C17H18N4O4 |
| Purity | |
| SMILES | |
| Form | Solid |
| Storage | |
| Shipping | |
| Catalog no. (Mfr.) | |
| Main SKU |
Compound Overview
PA-8 is a potent, selective, orally active antagonist of the PACAP type I (PAC1) receptor. It inhibits PACAP-induced phosphorylation of CREB at the PAC1 receptor, but not at VPAC1 or VPAC2 receptors, and it inhibits PACAP-induced cAMP elevation with an IC50 of 2 nM[1][2]. It is supplied as a white to yellow solid (C17H18N4O4, MW 342.35) at 97.00% purity.
Physical & Chemical Properties
| CAS Number | 878437-15-1 |
|---|---|
| Molecular Formula | C17H18N4O4 |
| Molecular Weight | 342.35 g/mol |
| Purity | 97.00% |
| Appearance | Solid |
| Color | White to yellow |
| SMILES | O=C1C(C(C2=CC=C(OCC=C)C(OC)=C2)CC(N3)=O)=C3N=C(N)N1 |
| Signaling Pathway | GPCR/G Protein |
| Solubility | In Vitro: DMSO: 25 mg/mL (73.02 mM; Requires sonication and warming and heat to 60°C; Hygroscopic DMSO has a significant impact on the solubility of product, please use newly opened DMSO) |
| Storage | Powder: -20°C, 3 years; 4°C, 2 years. In solvent: -80°C, 6 months; -20°C, 1 month. |
| Shipping | Room temperature in continental US; may vary elsewhere. |
Literature Cited
Sources cited in this description and in the In Vitro & In Vivo Data tab. Peer-reviewed publications that used this product are listed under References.
Safety
For Research Use Only. Not for use in diagnostic or therapeutic procedures, and not for human or veterinary use. Handle in accordance with the Safety Data Sheet and your institution's chemical hygiene plan.
In Vitro
| Solvent | Solubility | Notes |
|---|---|---|
| DMSO | 25 mg/mL (73.02 mM) | requires sonication and warming and heat to 60°C; use freshly opened DMSO (absorbed moisture lowers solubility) |
Aliquot the stock solution and store it at -80°C (up to 6 months) or -20°C (up to 1 month); avoid repeated freeze-thaw cycles.
In Vivo
Choose the formulation that suits the animal model and route of administration; percentages are volume ratios of the final working solution. Start from a clear DMSO stock (see In Vitro above), add the co-solvents one at a time in the order listed, mixing after each addition, and prepare the working solution fresh on the day of dosing. If precipitation or phase separation occurs, gentle warming or sonication can help.
Protocol 1
| Composition | 10% DMSO + 40% PEG300 + 5% Tween-80 + 45% saline |
|---|---|
| Result | ≥ 2.5 mg/mL (7.30 mM); clear solution |
| How to prepare | Gives a clear solution at ≥ 2.5 mg/mL (saturation not determined). For 1 mL of working solution: add 100 μL DMSO stock (25.0 mg/mL) to 400 μL PEG300; then 50 μL Tween-80; then 450 μL saline to bring the volume to 1 mL. Saline: dissolve 0.9 g sodium chloride in ddH2O and make up to 100 mL. |
Data provided by the manufacturer.
In Vitro
In PAC1/CHO cells, PA-8 (10 pM to 10 nM; 30 minutes) inhibits PACAP (1 nM)-induced CREB phosphorylation in a dose-dependent manner. In VPAC1/CHO and VPAC2/CHO cells, PACAP (1 nM) also induced CREB phosphorylation, but PA-8 (10 pM to 10 nM) does not inhibit this PACAP (1 nM)-induced CREB phosphorylation[1].
In Vivo
In male ddY mice, PA-8 (100 pmol/5 μL; intrathecal injection; once) treatment inhibits PACAP-induced aversive responses and mechanical allodynia in vivo[1]. PA-8 (3-30 mg/kg, p.o.) treatment dose-dependently attenuates the second phase of formalin-induced nociceptive responses, and PA-8 also prevents c-fos upregulation in the ipsilateral spinal cord dorsal horn[2].
| Animal Model | Male ddY mice (6 weeks old) injected with PACAP (100 pmol)[1] |
|---|---|
| Dosage | 100 pmol/5 μL |
| Administration | Intrathecal injection; once |
| Result | Inhibited PACAP-induced aversive responses and mechanical allodynia in vivo. |
Data provided by the manufacturer. Numbered citations refer to the Literature Cited list in the product description.
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PACAP/PAC1R activation promotes group 2 innate lymphoid cells-dependent allergic rhinitis via ERK pathway. Arch Biochem Biophys 2025 Oct:772:110564. PMID: 40713003
Design of peptide-based PAC1 antagonists combining molecular dynamics simulations and a biologically relevant cell-based assay. bioRxiv 2025 May 9:2025.04.16.649181. PMID: 40568092
