PIT (2,2'-Pyridylisatogen tosylate) is a selective and noncompetitive antagonist of the P2Y1 receptor, with IC50 of 0.14 μM for the human P2Y1 receptor. PIT antagonizes P2Y1 receptor signaling without affecting nucleotide binding. PIT is an irreversible antagonist of the ATP response of metabotropic purinergic receptors (P2Y family) in some smooth muscles. PIT may be utilized in the study of chronic bronchitis and asthma.

Physicochemical Properties

Molecular Formula	C20H16N2O5S
Molecular Weight	396.42
Exact Mass	396.078
CAS #	56583-49-4
PubChem CID	124333
Appearance	Brown to reddish brown solid powder
LogP	4.19
Hydrogen Bond Donor Count	1
Hydrogen Bond Acceptor Count	6
Rotatable Bond Count	2
Heavy Atom Count	28
Complexity	571
Defined Atom Stereocenter Count	0
InChi Key	MMPTYEXNPWSTOR-UHFFFAOYSA-N
InChi Code	InChI=1S/C13H8N2O2.C7H8O3S/c16-13-9-5-1-2-7-11(9)15(17)12(13)10-6-3-4-8-14-10;1-6-2-4-7(5-3-6)11(8,9)10/h1-8H;2-5H,1H3,(H,8,9,10)
Chemical Name	4-methylbenzenesulfonic acid;1-oxido-2-pyridin-2-ylindol-1-ium-3-one
HS Tariff Code	2934.99.9001
Storage	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.
Shipping Condition	Room temperature (This product is stable at ambient temperature for a few days during ordinary shipping and time spent in Customs)

Biological Activity

Targets	P2Y1 Receptor 0.14 μM μM (IC50)
ln Vitro	PIT (0.1–10 μM) has an IC50 value of 0.14 μM and reduces human P2Y1 receptor signaling in a non-competitive and dose-dependent manner[1]. PIT (0.1–10 μM) totally inhibits 2-MeSADP's agonistic activity[1]. PIT (1 nM-10 μM) reduces the buildup of inositol phosphates caused by the agonist 2-MeSADP in a dose-dependent manner[1]. PIT (1 nM–10 μM) inhibits P2Y1 receptor signaling that is triggered by the endogenous agonist ADP in a dose-dependent manner [1]. Higher concentrations (3-100 μM) inhibit ATP-mediated inward current with an IC50 value of 13.2 μM, whereas PIT (0.1-3 μM) increases ATP-responses 2-5 fold[2]. PIT exhibits low affinity for several membrane receptors, such as muscarinic, central benzodiazepine, H1, μ-opioid, dihydropyridine, batrachotoxin, α1, α2-adrenoceptors, 5-HT1A, 5-HT1B, 5-HT2, 5-HT3, D1, D2, and D1[2]. PIT has a pKi value of 5.3 and exhibits affinity to an adenosine (A1) receptor[2]. Irreversibly, PIT (12.5-50 μM) opposes ATP relaxations in guinea pig isolated taenia caeca [2].
ln Vivo	In rats with S-bromo-willardiine injection-induced tonic and tonicoclonic seizures, PIT (10 mg/kg; ip; for 5 days) dramatically protects the white matter and the cortical plate lesions against the insult[3].
References	[1]. 2,2'-Pyridylisatogen tosylate antagonizes P2Y1 receptor signaling without affecting nucleotide binding. Biochem Pharmacol. 2004 Jul 15;68(2):231-7. [2]. Potentiation by 2,2'-pyridylisatogen tosylate of ATP-responses at a recombinant P2Y1 purinoceptor. Br J Pharmacol. 1996 Mar;117(6):1111-8. [3]. Role of spin trapping and P2Y receptor antagonism in the neuroprotective effects of 2,2'-pyridylisatogen tosylate and related compounds. Eur J Pharmacol. 2002 May 24;444(1-2):53-60.

Solubility Data

Solubility (In Vitro)

DMSO: 83.33 mg/mL (210.21 mM )

Solubility (In Vivo)

Solubility in Formulation 1: ≥ 2.08 mg/mL (5.25 mM) (saturation unknown) in 10% DMSO + 90% (20% SBE-β-CD in Saline) (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 20.8 mg/mL clear DMSO stock solution to 900 μL of 20% SBE-β-CD physiological saline solution and mix evenly. 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.  (Please use freshly prepared in vivo formulations for optimal results.)

Preparing Stock Solutions		1 mg	5 mg	10 mg
	1 mM	2.5226 mL	12.6129 mL	25.2258 mL
	5 mM	0.5045 mL	2.5226 mL	5.0452 mL
	10 mM	0.2523 mL	1.2613 mL	2.5226 mL

*Note: Please select an appropriate solvent for the preparation of stock solution based on your experiment needs. For most products, DMSO can be used for preparing stock solutions (e.g. 5 mM, 10 mM, or 20 mM concentration); some products with high aqueous solubility may be dissolved in water directly. Solubility information is available at the above Solubility Data section. Once the stock solution is prepared, aliquot it to routine usage volumes and store at -20°C or -80°C. Avoid repeated freeze and thaw cycles.