Hcyb1 is a potent and specific inhibitor of phosphodiesterase 2 (PDE2). It exhibits a high degree of selectivity for inhibiting PDE2A with an IC50 value of 0.57 μM. In addition, Hcyb1 displays over 250-fold selectivity against other recombinant members of the PDE family. Moreover, its pharmacological actions include neuroprotective and antidepressant-like effects, which are believed to be mediated through the cAMP/cGMP-CREB-BDNF signaling pathway [1].

Hcyb1 increases cGMP levels by 1.7~2.3 folds after 10-minute treatment at concentrations of 1~100 nM [1]. Hcyb1 increases both cGMP and cAMP levels 24 hours after treatment at the concentrations of 1 nM [1]. Hcyb1 treatment also increases the levels of phosphorylation of CREB and BDNF in HT-22 cells for 24 hours [1]. Hcyb1 promotes HT-22 cell viability and increase the cGMP and cAMP accumulation in HT-22 cells [1]. Hcyb1 exhibits the concentration- and time-dependent effects on cell viability in HT-22 cells [2]. Cell Proliferation Assay [1] Cell Line: HT-22 cells Concentration: 1 pM, 0.01 nM, 0.1 nM, 1 nM, 0.01 μM, 0.1 μM, 1 μM, 10 μM Incubation Time: 24 hours Result: The cell viability was significantly increased when treatment HT-22 cells with Hcyb1 at concentrations of 0.1 nM and 1 nM for 24 hours. The time-dependent effects showed that the cell viability was significantly increased from 12 to 24 hours when treatment at concentration of 1 nM. The maximal effects peaked at 24 hours after treatment. Western Blot Analysis [1] Cell Line: HT-22 cells Concentration: 1 nM Incubation Time: 24 hours Result: Induced a significant increase in the phosphorylation of CREB. BDNF expression was also significantly upregulated at the same concentration.

Hcyb1 (0.5, 1, and 2 mg/kg, i.g.) decreases the immobility time in both forced swimming and tail suspension tests, without altering locomotor activity [3]. Animal Model: Male imprinting control region (ICR) mice, weighing between 20 and 25 g [3] Dosage: 0.5, 1, and 2 mg/kg Administration: Gavage (i.g.) Result: Exhibited dose-dependent reduction in immobility time at doses of 0.5, 1, 2 mg/kg (i.g.).