Tandospirone (hydrochloride)

Tandospirone (SM-3997) hydrochloride is a potent and selective 5-HT_1A receptor partial agonist, with a K_i of 27 nM. Tandospirone hydrochloride has anxiolytic and antidepressant activities. Tandospirone hydrochloride can be used for the research of the central nervous system disorders and the underlying mechanisms^[1][2][3]. In Vitro: Tandospirone (SM-3997) hydrochloride is approximately two to three orders of magnitude less potent at 5-HT₂, 5-HT_1C, α1-adrenergic, α2-adrenergic and dopamine D1 and D2 receptors (K_i values ranging from 1300 to 41000 nM) than 5-HT_1A^[1].
Tandospirone hydrochloride is essentially inactive at 5-HT_1B receptors; 5-HT uptake sites; beta-adrenergic, muscarinic cholinergic, and benzodiazepine receptors^[1].
Tandospirone hydrochloride activates postsynaptic 5-HT_1A receptor coupled with G-protein (G_i/o), resulting in inhibition of protein kinase A (PKA)-mediated protein phosphorylation and neuronal activity^[1]. In Vivo: Tandospirone (SM-3997) hydrochloride (10-80 mg/kg; i.p.) inhibits freezing behavior in the conditioned fear stress-induced freezing behavior rat model^[3].
Tandospirone hydrochloride exhibits the anxiolytic effect dependent on the plasma concentration of at 0.5 hours but not 4 hours^[3].