Dizocilpine-derived K2060 exhibits enhanced blockage at NMDA receptors with impaired Mg 2+ block and provides strong protection against audiogenic seizures
Year: 2026
Type: preprint
Abstract: Background and Purpose Voltage-dependent Mg 2+ block is a defining feature of the GluN1/GluN2 subtype of N -methyl-D-aspartate receptors (NMDARs). We tested how impaired Mg 2+ block at GluN1/GluN2A receptors mutated at the GluN2A-N615 position modifies inhibition by dizocilpine-derived K2060 compared with clinically used memantine and ketamine. Experimental Approach Electrophysiological recordings were performed on recombinant wild-type (WT) and mutated GluN1/GluN2A receptors expressed in HEK293T cells. Acute hippocampal slice electrophysiology and behavioural studies were conducted in WT and knock-in GluN2A-N615S mice. In vivo tolerability and efficacy were evaluated using open field testing, prepulse inhibition (PPI), and protection against audiogenic seizures (AGS). Key Results Mg 2+ reduced the apparent potency of all three blockers and slowed onset at the GluN1/GluN2A-WT receptor. These Mg 2+ -dependent effects were absent or markedly reduced at the GluN1/GluN2A-N615S and GluN1/GluN2A-N615K receptors. In addition, K2060 showed slower unbinding and greater trapping than memantine. In hippocampal slices from GluN2A-N615S mice, K2060 exhibited enhanced but slower onset inhibition than memantine and ketamine. In vivo , K2060 caused no overt behavioural disruption at 5 mg/kg ( i.p. ) and did not further disrupt PPI. All three blockers protected GluN2A-N615S mice against AGS at 5 mg/kg ( i.p. ); only K2060 remained protective at 1 mg/kg ( i.p. ). Conclusions and Implications Impaired Mg²⁺ block removes a physiological constraint on the action of NMDAR blockers. K2060 exhibited the most favourable pharmacological profile, supporting its further evaluation for studies with NMDAR hyperfunction models. Additional pharmacokinetic, safety, and disease-model studies are warranted. What is already known? NMDAR blockers, including memantine, ketamine and the dizocilpine-derived K2060, bind within the ion channel pore, where Mg 2+ can influence their potency and kinetics. The GluN2A-N615S variant reduces Mg 2+ block and causes NMDAR hyperfunction associated with neuronal hyperexcitability and audiogenic seizure susceptibility in mice. What does this study add? Impaired Mg 2+ block of the mutated NMDARs at the GluN2A-N615 position removes Mg 2+ -dependent modulation of blocker potency and kinetics. K2060 produces sustained inhibition of recombinant and endogenous GluN2A-N615S-containing NMDARs and protects GluN2A-N615S mice against AGS at a lower dose than memantine or ketamine. What is the clinical significance? GRIN2A pore variants that reduce Mg 2+ block alter sensitivity to NMDAR blockers. K2060 warrants further preclinical evaluation for NMDAR hyperfunction animal models.
Authors: Marharyta Kolcheva, Jakub Netolicky, Anna Misiachna, Natalia Rybalko, Petra Zahumenska, Jovana Doderovic, Alena Pakhomova, Claudia Valentina De Sanctis, Gregory Klein Schneider, Katarina Hemelikova, Kristyna Rehakova, Stepan Kortus, Rostislav Turecek, Jan Korabecny, Ondrej Soukup, Marek Ladislav, Martin Horak
Language: English
Subfield: Cellular and Molecular Neuroscience
Field: Neuroscience
Domain: Life Sciences
Open Access status: green
OpenAlex ID: W7221716729