Ketamine is a rapid acting general anesthetic and NMDA receptor antagonist. It was developed in 1963 as a replacement for phencyclidine (PCP). It was used for veterinary purposes in Belgium. In 1970, it was approved by the FDA after in 1964 it was proven to only produce minor hallucinogenic effects and shorter psychotomimetic effects compared to PCP. Ketamine acts on NMDA receptors, opioid receptors, monoaminergic receptors, muscarinic receptors and voltage sensitive Ca ion channels. Ketamine is injected intravenously or intramuscularly then diffuses into the brain across the blood-brain barrier. Ketamine antagonizes NMDA receptors at the 3A subunit. This prevents glutamate form activating the receptor and calcium from entering the postsynaptic neuron. This causes hyperpolarization of the neuron and prevents depolarization. This leads to an anaesthesia and analgesia.

Ketamine NMDA Antagonist Pathway References