Flesinoxan is a hypotensive agent and a potent, high affinity and selective 5-hydroxytryptamine1A (5-HT1A) receptor agonist with an EC50 value of 24 nM. Flesinoxan also has effective anxiolytic/antidepressant effects[1][2][3].

Flesinoxan acts as a partial agonist at postsynaptic and as a full agonist at presynaptic 5-HT1A receptors. The capacity of Flesinoxan to antagonize the effect of 5-HT on CA3 pyramidal neurons was similar to that of 8-hydroxy-2-(di-n-propylamino)-tetralin (8-OH-DPAT)[1]. The intravenous administration of Flesinoxan suppresses the firing activity of both CA3 pyramidal neurons and dorsal raphe 5-HT neurons. The acute brain penetration of [3H]Flesinoxan and [3H]8-OH-DPAT are determined. Nine minutes after intravenous administration, [3H]8-OH-DPAT reached significantly greater brain concentration than [3H]Flesinoxan[1].Subcutaneous administration of Flesinoxan and 8-OH-DPAT produce a dose-dependent hypothermia. The Flesinoxan-induced hypothermia is significantly attenuated by prior administration of the non-selective 5-HT1A antagonist pindolol and the 5-HT1/2 antagonist methysergide. Similar degrees of hypothermia are achieved with 3 mg/kg of Flesinoxan and 0.5 mg/kg of 8-OH-DPAT. The maximal effect of Flesinoxan occurs 30 min later than that of 8-OH-DPAT and fades more slowly[1].

[1]. Hadrava V, et al. Characterization of 5-hydroxytryptamine1A properties of flesinoxan: in vivo electrophysiology and hypothermia study. Neuropharmacology. 1995 Oct;34(10):1311-26. [2]. Schoeffter P, et al. Centrally acting hypotensive agents with affinity for 5-HT1A binding sites inhibit forskolin-stimulated adenylate cyclase activity in calf hippocampus. Br J Pharmacol. 1988 Nov;95(3):975-85. [3]. Rodgers RJ, et al. Antianxiety and behavioral suppressant actions of the novel 5-HT1A receptor agonist, flesinoxan. Pharmacol Biochem Behav. 1994 Aug;48(4):959-63.