Osutidine

Osutidine is a selective histamine H₂ receptor antagonist, can effectively inhibit histamine-stimulated gastric acid secretion. Osutidine does not affect [¹⁴C]aminopyrine accumulation stimulated by carbachol or dibutyryl-cAMP. Osutidine is insurmountable and includes non-competitive inhibition. Osutidine can be used for the study of gastric mucosal injury^[1][2]. In Vitro:Osutidine inhibits the accumulation of 10^-4 M histamine-stimulated [¹⁴C]AP in isolated canine gastric mucosal cells in a concentration-dependent manner, with an IC₅₀ of 1.85 × 10^-6 M^[1].
Osutidine only slightly inhibits the accumulation of [¹⁴C]AP stimulated by 10^-4 M dbcAMP in isolated canine gastric mucosal cells (maximum inhibition of 20-32%)^[1].
Osutidine shifts the histamine concentration-response curve to the right and reduces the maximum response in isolated canine gastric mucosal cells, with a Schild plot slope of 2.01, indicating that H₂ receptor antagonism is insurmountable and non-competitive^[1].
Osutidine binds tightly to H₂ receptors in isolated canine gastric mucosal cells and is difficult to reverse by washing, indicating that it has slow dissociation properties^[1].
Osutidine has (-)-S-T-593 as its main active enantiomer responsible for H₂ receptor antagonism, while (+)-R-T-593 exhibits weak activity^[1].
In Vivo:Osutidine (6-60 mg/kg, i.p., once) has a significant protective effect on the gastric mucosa in Sprague-Dawley rats, significantly inhibiting ethanol-induced gastric mucosal damage in a dose-dependent manner^[2].