RECEPTEURS NMDA
A protonated H+-sensor stabilizes the NR1-NR2B heterodimer in  low-conductance state
Polyamines (spermine, spermidine) shield the H+-sensor from protons thus attenuating the inhibition by proton  and potentialising the influx of Ca 2+
Ifenprodil enhances the sensitivity
to protons
From Chizh et al.  TiPS 22: 636-642 (2001)
Interactions between endogenous modulators and ifenprodil-like selective antagonists of NR2B-containing NMDA receptors
FARM 2146 - 2003-2004