Terahertz Photons Enhance the Transmission of Calcium Ions Through NMDA Receptor

N-Methyl-D-aspartate (NMDA) receptors, also glutamate-gated calcium ion channels, play essential roles in synaptic transmission and plasticity and hence influence learning and memory. Biomolecules exhibit distinct spectra in the terahertz (THz) frequency range, allowing THz photons to influence their functioning and the resultant cellular activities. Previous studies have validated that THz photons in resonance with the key chemical bonds lining the voltage-gated calcium channel can enhance its permeability. In this work, we focus on the effect of specific THz electromagnetic fields on the permeation of the NMDA receptor channel. Molecular dynamics (MD) simulations demonstrate that the 35.4 and 42.4 THz fields could effectively suppress the free energy profiles of calcium ions permeating the NMDA receptor channel, with the largest decrease of 16.25 kJ/mol. The channel permeability is revealed enhanced by THz photons resonating with key amino acids especially carboxyl groups at the binding sites. The findings predict potential applications of THz radiation in treating NMDA receptor dysfunction and related diseases, offering a new physical treatment method.