Ketamine for Depression: How does it work? We ran across a useful review of the basic science literature in an interview of David Nichols on the Psych Congress Network. http://www.psychcongress.com/video/ketamine-quick-guide-receptors-19116 Although ketamine blocks the NMDA subtype of glutamate receptors (blocks an excitatory neurotransmitter) the net effect seems to be an increase in excitatory neurotransmission. This image from Nature may help …