New Drug Lifts Hard To Treat Depression In Hours- New Scientist

This is different than ketamine, due to it's binding site. GLYX-13 binds at the glycine binding site of the NMDAR, while ketamine binds at the allosteric binding site. Magnesium instigates a voltage-dependent block of the calcium channel itself. All 3 of these substances have been shown to improve depression symptoms. Memantine is also an NMDA receptor antagonist, but at a binding site within the channel itself. This means that it's binding is dependent on extracellular glutamate and the membrane's electrical potential. It may also have some ability to alleviate depression.

Here is a figure I just made to illustrate it.

Interestingly enough, some nootropics in the racetam category also modulate the NMDAR by binding the allosteric site. They can also help alleviate depression.