Edelinontrine (PF-04447943) is a potent inhibitor of human recombinant PDE9A (IC50=12 nM) with >78-fold selectivity, respectively, over other PDE family members (IC50>1000 nM).
pf-04447943 is a potent and selective inhibitor of pde9 [1].phosphodiesterase 9 (pde9) selectively degrades cgmp and limits the cgmp-mediated signal transduction which occurs following glutamate binding to nmda receptors. pde9 in cortex and hippocampus of rodents and humans play an important role in memory and learning [1].pf-04447943 have high affinity with ki of 2.8, 4.5 and 18 nm for human, rhesus and rat recombinant pde9 respectively and high selectivity for pde9 versus pdes1- 8 and 10 -11. in cultured hippocampal neurons, pf-04447943 (30-100 nm) significantly increased neurite outgrowth and synapse formation. also, pf-04447943 (100 nm) significantly facilitated hippocampal slice ltp evoked by a weak tetanic stimulus [1].in mice model, pf-04447943 (1 mg/kg) significantly reduced the time spent interacting with the female mouse during the second encounter 24 h later compared to the first encounter, which suggested that pf-04447943 enhanced recognition memory. while, pf-04447943 (3 or 10 mg/kg) didn’t change the interaction times for each encounter. these results suggested that pf-04447943 enhanced memory with an inverted u-shaped dose-response efficacy curve [1].
Based on i.v. and p.o. dosing, pharmacokinetic studies with Edelinontrine in the rat indicates a Tmax of 0.3 h, T1/2 of 4.9 h, Cl of 21.7 mL/min/kg and an oral bioavailability of 47%. Thirty minutes following oral administration in rats (1-30 mg/kg), Edelinontrine concentrations dose-dependently increase in blood, brain and cerebrospinal fluid (CSF). The brain:plasma exposure ratios 30 min after dosing range from 0.13 at the 1 mg/kg dose to 0.33 at the 30 mg/kg dose. CSF levels are approximately 50% of brain levels. In mice, Edelinontrine (3, 10, 30 mg/kg p.o.) dose-dependently increases plasma and brain concentrations of Edelinontrine while the brain to plasma ratio ranged from 0.26 to 0.7 although this is not entirely dose dependent. CSF cGMP levels increase in a dose-dependent manner from a basal level of 3 pmol/mL to 13.3 pmol/mL (3.5-fold) at the 30 mg/kg dose. CSF cGMP levels also increase in a dose-dependent manner from a basal level of 3 pmol/mL in vehicle treated animals to 13.3 pmol/mL (3.5-fold) at the 30 mg/kg dose. CSF cGMP levels are elevated at all doses tested with a maximal effect of 3.5 fold increase above controls at 30 mg/kg[2].
[1]hutson ph, finger en, magliaro bc, et al. the selective phosphodiesterase 9 (pde9) inhibitor pf-04447943(6-[(3s,4s)-4-methyl-1-(pyrimidin-2-ylmethyl)pyrrolidin-3-yl]-1-(tetrahydro-2h-pyran-4-yl)-1,5-dihydro-4h-pyrazolo[3,4-d]pyrimidin-4-one) enhances synaptic plasticity and cognitive function in rodents. neuropharmacology, 2011, 61(4): 665-676.
