N-Methyl-D-aspartic (NMDA) receptors are ionotropic glutamate receptors widely expressed in the central nervous system, where they mediate phenomena as diverse as neurotransmission, information processing, synaptogenesis, and cellular toxicity. They function as glutamate-gated Ca2+-permeable channels, which require glycine as co-agonist, and can be modulated by many diffusible ligands and cellular cues, including mechanical stimuli. Previously, we found that in cultured astrocytes, shear stress initiates NMDA receptor-mediated Ca2+ entry in the absence of added agonists, suggesting that more than being mechanosensitive, NMDA receptors may be mechanically activated. Here, we used controlled expression of rat recombinant receptors and non-invasive on-cell single-channel current recordings to show that mild membrane stretch can substitute for the neurotransmitter glutamate in gating NMDA receptor currents. Notably, stretch-activated currents maintained the hallmark features of the glutamate-gated currents, in...