Researchers have been experimenting with ketamine with interesting results.
Ketamine [from wikipedia] is a dissociative anesthetic for use in human and veterinary medicine. Ketamine has a wide range of effects in humans, including analgesia, anesthesia, hallucinations, arterial hypertension, and bronchodilation. It is primarily used for the induction and maintenance of general anesthesia, usually in combination with some sedative drug. Other uses include sedation in intensive care, analgesia (particularly in emergency medicine), and treatment of bronchospasm. It is also a popular anesthetic in veterinary medicine.
Because of these side effects, it has also become a somewhat popular recreational drug.
Here's the latest from physorg:
A new study has revealed more about how the medication ketamine, when used experimentally for depression, relieves symptoms of the disorder in hours instead of the weeks or months it takes for current antidepressants to work...Sounds like it may still be several years down the line, but being able to have antidepressants that take hours instead of months to work would make my job much easier. Seems that we may also have a new mechanism of antidepressant action that focuses on AMPA and the glutamate system(an inhibitory neurotransmitter) instead of serotonin.
Ketamine blocks a receptor called NMDA on brain cells, an earlier NIMH study in humans had shown, but the new study in mice shows that this is an intermediate step. It turns out that blocking NMDA increases the activity of another receptor, AMPA, and that this boost in AMPA is crucial for ketamine’s rapid antidepressant actions. The study was reported online in Biological Psychiatry on July 23, by NIMH researchers Husseini K. Manji, MD, Guang Chen, MD, PhD, Carlos Zarate, MD, and colleagues.