NMDA receptor antagonists
NMDA receptor antagonists are a class of anesthetics that work to antagonize, or inhibit the action of, the Nmethyl daspartate receptor.
The main agent in this group used in veterinary medicine, ketamine, is primarily used as a dissociative anaesthetic: the patient looks as if it is conscious (e.g. its eyes are open) but does not respond to external stimuli. However, ketamine also binds to the receptors found in the brain called the NMDA or N-methyl-D-aspartate receptors. Ketamine is an antagonist at NMDA receptors – it binds to these receptors and blocks them. The result is analgesia that is particularly useful in some specific types of chronic pain, such as neuropathic pain.