Betahistine is an orally active histamine H1 receptor agonist and a H3 receptor antagonist[1]. Betahistine is used for the study of rheumatoid arthritis (RA)[3].

Betahistine (0-10 μM) inhibits [125I]iodoproxyfan binding to membranes of CHO (rH3(445)R) and CHO (hH3(445)R) cells with IC50 values of 1.9 μM and 3.3 μM, respectively. Lead to Ki values of 1.4 μM and 2.5 μM, respectively[2].Betahistine (0-10 μM) has a regulating function on cAMP formation in CHO (rH3(445)R), CHO (rH3(413)R), and CHO (hH3(445)R) cells. At low concentrations, betahistine behaves an apparent inverse agonist, and progressively enhances cAMP formation with EC50 values of 0.1 nM, 0.05 nM and 0.3 nM, respectively. In contrast, at concentrations higher than 10 nM, betahistine inhibits cAMP formation with an EC50 value of 0.1 μM in CHO (rH3(445)R) and full agonist activity[2].

Betahistine (intraperitoneal or oral administration; 0.1-30 mg/kg; single dose) with acute administration has increased tele-methylhistamine (t-MeHA) levels with an ED50 of 0.4 mg/kg, indicating the inverse agonism. Besides, after acute oral administration, it increases t-MeHA levels with an ED50 of 2 mg/kg in male Swissmice[2].Betahistine (oral adminstration; 1 and 5 mg/kg; daily for 3 weeks) attenuates the severity of arthritis and reduces the levels of pro-inflammatory cytokines in the paw tissues of CIA mice[3]. Animal Model: Collagen-induced arthritis (CIA) DBA/1 male mouse model[3]

[1]. Poyurovsky M, et al. The effect of betahistine, a histamine H1 receptor agonist/H3 antagonist, on olanzapine-induced weight gain in first-episode schizophrenia patients. Int Clin Psychopharmacol. 2005 Mar;20(2):101-3. [2]. Gbahou F, et al. Effects of betahistine at histamine H3 receptors: mixed inverse agonism/agonism in vitro and partial inverse agonism in vivo.J Pharmacol Exp Ther. 2010 Sep 1;334(3):945-54. [3]. Tang KT, et al. Betahistine attenuates murine collagen-induced arthritis by suppressing both inflammatory and Th17 cell responses.Int Immunopharmacol. 2016 Oct;39:236-245.