We know that ketamine modulates additional receptor types, but the glutamate receptors seem to play the most important role in ketamine’s ability to treat depression and anxiety.
Neurons have a number of different binding sites for glutamate, but when it comes to ketamine, two are of particular interest: the NMDA receptor and the AMPA receptor.
By increasing the level of glutamate transmission while also shifting the balance of glutamate activation from NMDA to AMPA receptors, ketamine rapidly upregulates neuronal production and release of BDNF (brain-derived neurotrophic factor). Aptly called fertilizer for the brain, BDNF is a protein that helps promote the growth, maintenance, and survival of neurons—in other words, it enhances neuroplasticity.