γ-aminobutyric acid  (TargetMol)

Journal: iScience

Article Title: Context-dependent NMDA receptor dysfunction predicts seizure treatment in mice with human GluN1 variant

doi: 10.1016/j.isci.2025.114301

Figure Lengend Snippet: Isolated NMDARs show loss of function in mice with GluN1 Y647S +/− patient variant (A) Schematic showing the position of the Y647S mutation in the M3 transmembrane domain of the GluN1 NMDAR subunit (top), structure of the human GluN1-GluN2A NMDAR tetramer (PDB: 6IRF ) highlighting the Y647 site in the channel pore (bottom). (B) Tyrosine residue at the 647 th position of GluN1 is mutated to serine, causing severe seizures and intellectual disability in the patient. Mutant mice ( Grin1 Y647S +/− ) replicating the patient phenotype were used for slice electrophysiology. (C) Coronal prefrontal cortex slices from adult WT and mutant (Y647S +/− ) mice were used to record synaptic currents evoked by electrical stimulation of glutamate release in layer 5 pyramidal (L5 Pyr) neurons. (D) Schematic with position of stimulating and recording electrodes in the brain slice. Isolated AMPAR EPSCs measured using cesium gluconate patch pipettes in the presence of GABAR blockers at −60 mV in WT and Y647S +/− at increasing stimulus strengths. (E) AMPAR EPSC peak amplitude in WT and Y647S +/− at different stimuli is identical . (F) Paired pulse ratio at 20 ms interval is similar in WT and Y647S +/− neurons . (G) Isolated NMDAR EPSCs measured with AMPARs blocked at +40 mV in WT and Y647S +/− . (H) NMDAR EPSC peak amplitude is reduced in Y647S +/− neurons (∗ p < 0.05, ∗∗ p < 0.01, Sidak’s post hoc). (I) AMPA to NMDA ratio in WT and Y647S +/− neurons (∗ p < 0.05, unpaired t test). (Inset), EPSCs at −60 and +40 mV in WT and Y647S +/− , dotted line indicates NMDAR component at +40 mV. (J) Summary schematic showing preserved AMPAR but reduced NMDAR currents in Grin1 Y647S +/− mice. Bars denote mean ± SEM.

Article Snippet: Gamma-aminobutyric acid receptor (GABAR) blockers (Picrotoxin 20 μM, Alomone Labs , CGP52432 1 μM, Tocris ) were included in all recordings, and AMPAR blocker (CNQX or NBQX 20 μM, Alomone Labs ) was used to isolate synaptic NMDAR currents at +40 mV.

Techniques: Isolation, Variant Assay, Mutagenesis, Residue, Slice Preparation

Journal: iScience

Article Title: Context-dependent NMDA receptor dysfunction predicts seizure treatment in mice with human GluN1 variant

doi: 10.1016/j.isci.2025.114301

Figure Lengend Snippet: Paradoxically prolonged NMDAR integration in Grin1 Y647S +/− mice (A) Schematic showing that a single stimulus evokes limited glutamate release that activates only synaptic receptors, while repetitive high frequency stimulation causes glutamate spillover onto the dendrite, generating a dendritic plateau potential. (B) Average NMDAR plateau potentials in WT and Y647S +/− neurons evoked by 50 Hz stimulation, measured in the presence of AMPAR and GABAR blockers. (Inset) Plateau potential amplitude (normalized to the spike threshold) at different stimulus intensities in WT and Y647S +/− (∗ p < 0.05, Sidak’s post hoc). (C) NMDAR plateau potentials show extended duration in Y647S +/− neurons compared to WT at multiple stimulus intensities. (D) Area under the plateau potential for the 1 s period post-stimulation (late area) at different stimuli in WT and Y647S +/− (∗∗∗∗ p < 10 −4 , Sidak’s post hoc). (E) Total duration of the plateau potential (at 50 μA stimulation) in WT and Y647S +/− neurons (∗ p < 0.05, unpaired t test).

Article Snippet: Gamma-aminobutyric acid receptor (GABAR) blockers (Picrotoxin 20 μM, Alomone Labs , CGP52432 1 μM, Tocris ) were included in all recordings, and AMPAR blocker (CNQX or NBQX 20 μM, Alomone Labs ) was used to isolate synaptic NMDAR currents at +40 mV.

Techniques: