PIT

PIT (2,2'-Pyridylisatogen tosylate) is a selective and non-competitive antagonist of P2Y1 receptor with an IC₅₀ value of 0.14 μM for human P2Y1 receptor. PIT antagonizes P2Y1 receptor signaling without affecting nucleotide binding. PIT is an irreversible antagonist of responses to ATP at metabotropic purinoceptors (of the P2Y family) in some smooth muscles. PIT can be used for the research of chronic bronchitis and asthma^[1][2][3]. In Vitro:PIT (0.1-10 μM) non-competitively and dose-dependently diminishs human P2Y1 receptor signaling with an IC₅₀ value of 0.14 μM^[1].
PIT (0.1-10 μM) completely blocks the agonist activity of 2-MeSADP^[1].
PIT (1 nM-10 μM) dose-dependently inhibits the accumulation of inositol phosphates induced by the agonist 2-MeSADP^[1].
PIT (1 nM-10 μM) dose-dependently blocks the P2Y1 receptor signaling induced by the endogenous agonist ADP^[1].
PIT (0.1-3 μM) increases ATP-responses 2-5 fold, while higher concentrations (3-100 μM) inhibits ATP-mediated inward current with an IC₅₀ value of 13.2 μM^[2].
PIT shows a low affinity for a range of membrane receptors, including: α₁, α₂-adrenoceptors, 5-HT_1A, 5-HT_1B, 5-HT₂, 5-HT₃, D₁, D₂, muscarinic, central benzodiazepine, H₁, μ-opioid, dihydropyridine and batrachotoxin receptors with pK_i values of <5^[2].
PIT shows affinity to an adenosine (A₁) receptor with a pK_i value of 5.3^[2].
PIT (12.5-50 μM) irreversibly antagonizes relaxations of ATP in guinea-pig isolated taenia caeca^[2]. In Vivo:PIT (10 mg/kg; i.p.; for 5 days) significantly protects both the white matter and the cortical plate lesions against the insult in mice with S-bromo-willardiine injection induced tonic and tonicoclonic seizures^[3].