Pitolisant hydrochloride is a potent and selective nonimidazole inverse agonist at the recombinant human histamine H3 receptor (K_i=0.16 nM).

On the stimulation of guanosine 5′-O-(3-[³⁵S]thio)triphosphate binding to this receptor, Pitolisant (BF2.649) behaves as a competitive antagonist with a K_i value of 0.16 nM and as an inverse agonist with an EC₅₀ value of 1.5 nM and an intrinsic activity ~50% higher than that of ciproxifan. Pitolisant displaces [¹²⁵I]iodoproxyfan binding from mouse brain cortical membranes with an IC₅₀ value of 26.4±4.5 nM. Taking into account the K_d value of the radioligand (161±9 pM), the deduced K_i value for Pitolisant is 14±1 nM. Pitolisant displaces [¹²⁵I]iodoproxyfan binding from membranes of rat glioma C6 cells stably expressing the human H₃ receptor with an IC₅₀ value of 4.2±0.2 nM. Taking into account the K_d value of the radioligand (50±4 pM), the deduced K_i value for Pitolisant is 2.7±0.5 nM. Pitolisant progressively reverses this response with a Hill coefficient close to unity and an IC₅₀ value of 330±68 nM, leading to a K_i value of 17±4 nM. Pitolisant elicits a dose-dependent decrease of the basal-specific [³⁵S]GTPγS binding to membranes with a maximal effect corresponding to 75±1% of the basal-specific binding and an EC₅₀ value of 1.5±0.1 nM.

西域 has not independently confirmed the accuracy of these methods. They are for reference only.

The administration of Pitolisantat a single dose of 10 mg/kg 30 min before a single dose of LY170053 (2 mg/kg b.w.) also significantly affects immobility time in the FST. Subsequent administration of the aforementioned drug sequence in mice statistically significantly increases the duration of immobility in comparison to the time determined in the control group in the FST. It decreased locomotor activity as well. In contrast, the results obtained in subchronic treatment after fifteen administrations of both drugs (Pitolisant 10 mg/kg b.w., and after 30 min LY170053 2 mg/kg b.w., and again after 4 h LY170053 2 mg/kg b.w.) show that the administration of Pitolisant followed by that of LY170053 equalized the locomotor activity in mice; in comparison to the level of motility in the control group, to which only Pitolisant is administered. More importantly, this combination of drugs significantly reduces immobility time to the level obtained in the control group in the forced swim test in mice [one-way ANOVA; F _(3,20)=4.226,P=0.0181]. Rats given Pitolisant (10 mg/kg) during the conditioning phase stayed 502±94 s on the paired texture, a value not statistically different from that of controls, indicating that Pitolisant did not support place preference.

西域 has not independently confirmed the accuracy of these methods. They are for reference only.

The administration of Pitolisantat a single dose of 10 mg/kg 30 min before a single dose of LY170053 (2 mg/kg b.w.) also significantly affects immobility time in the FST. Subsequent administration of the aforementioned drug sequence in mice statistically significantly increases the duration of immobility in comparison to the time determined in the control group in the FST. It decreased locomotor activity as well. In contrast, the results obtained in subchronic treatment after fifteen administrations of both drugs (Pitolisant 10 mg/kg b.w., and after 30 min LY170053 2 mg/kg b.w., and again after 4 h LY170053 2 mg/kg b.w.) show that the administration of Pitolisant followed by that of LY170053 equalized the locomotor activity in mice; in comparison to the level of motility in the control group, to which only Pitolisant is administered. More importantly, this combination of drugs significantly reduces immobility time to the level obtained in the control group in the forced swim test in mice [one-way ANOVA; F _(3,20)=4.226,P=0.0181]. Rats given Pitolisant (10 mg/kg) during the conditioning phase stayed 502±94 s on the paired texture, a value not statistically different from that of controls, indicating that Pitolisant did not support place preference.

西域 has not independently confirmed the accuracy of these methods. They are for reference only.

• . Ligneau X, et al. BF2.649 [1-{3-[3-(4-Chlorophenyl)propoxy]propyl}piperidine, hydrochloride], a nonimidazole inverse agonist/antagonist at the human histamine H3 receptor: Preclinical pharmacology. J Pharmacol Exp Ther. 2007 Jan;320(1):365-75.  [Content Brief]

  . Dudek M, et al. H3 histamine receptor antagonist pitolisant reverses some subchronic disturbances induced by LY170053 in mice. Metab Brain Dis. 2016 Oct;31(5):1023-9.  [Content Brief]

  . Uguen M, et al. Preclinical evaluation of the abuse potential of Pitolisant, a histamine H? receptor inverse agonist/antagonist compared with CRL 40476. Br J Pharmacol. 2013 Jun;169(3):632-44.  [Content Brief]