Cipralisant is a potent and selective histamine H3 receptor antagonist in vivo, and an agonist in vitro, with a pKi of 9.9 for histamine H3 receptor and a Ki of 0.47 nM for rat histamine H3 receptor; Cipralisant has entered in clinical trials for the treatment of attention-deficit hyperactivity disorder.
Cipralisant (GT-2331) is a potent histamine H3 receptor antagonist with a pKi of 9.9[1] and a Ki of 0.47 nM for rat histamine H3 receptor[2]. Cipralisant acts as a full agonist at the recombinant rat histamine H3 receptor in vitro, and potently inhibits forskolin-induced cAMP accumulation with an EC50 of 0.23 nM. Cipralisant increases the basal [35S]GTPγS binding activities in membranes from HEK cells expressing the rat histamine H3 receptor (EC50, 5.6 nM)[2].
Cipralisant (GT-2331) acts as an antagonist of histamine H3 receptor, and blocks R-α-methylhistamine (a histamine H3 receptor agonist)-induced water intake at 10 mg/kg via oral administration in rats[2].
[1]. Tedford CE, et al. High antagonist potency of GT-2227 and GT-2331, new histamine H3 receptor antagonists, in two functional models. Eur J Pharmacol. 1998 Jun 26;351(3):307-11. [2]. Ito S, et al. Detailed pharmacological characterization of GT-2331 for the rat histamine H3 receptor. Eur J Pharmacol. 2006 Jan 4;529(1-3):40-6.