Antidepressants based on ketamine?
American scientists have explained the mechanism of action of ketamine in depressionCopper news
American scientists have found out the mechanism that allows the drug for anesthesia ketamine to quickly and effectively eliminate the symptoms of depression resistant to other groups of drugs, reports EurekAlert! (Yale team describes secrets of 'magic' antidepressant).
It is estimated that about 40 percent of patients with depression do not experience relief when taking antidepressants, and many more of these drugs begin to take effect after months and years of continuous use.
A number of studies conducted over the past 10 years have shown that ketamine at a dose lower than required to achieve anesthesia, after a single administration, significantly reduces or completely eliminates the manifestations of depression, including in patients with bipolar (manic-depressive) disorder. Moreover, this effect persists from 7 to 10 days after injection. It has also been shown that the drug is able to eliminate suicidal thoughts in depressed patients.
The mechanism of such action of ketamine, which is a dissociative hallucinogen, and, like other psychotropic substances, a controlled drug (the circulation of which is limited due to possible abuse), has not been clarified.
Dissociative psychoactive substances distort the nature of perception of sound and visual images and cause a feeling of alienation – dissociation – from everything around and from themselves. These effects are not literally hallucinations. Dissociative substances act by changing the distribution of the neurotransmitter glutamate in the brain, which provides pain perception, reaction to the surrounding reality and memory.
Researchers from Yale University have mapped the molecular action of ketamine in the prefrontal cortex of rats – the part of the brain responsible for executive functions (choosing the direction of thoughts, behavior patterns and the object of attention, as well as planning and abstract thinking).
It turned out that ketamine causes the rapid formation of new connections between neurons (synapses) to replace those destroyed by chronic stress in depression. (In the picture taken by the authors of the study, the synapses are marked with arrows.)
The key enzyme of this process turned out to be mTOR (mammalian target of rapamycin), which controls the synthesis of proteins necessary for the formation of synapses.
It is also possible that the blocking effect of ketamine on the glutamate NMDA receptor is important - in 2009, researchers from the University of California at Davis showed that this receptor is directly involved in building connections between nerve cells.
According to one of the researchers, George Aghajanian, the discovered molecular mechanism opens the way for the creation of antidepressants similar to ketamine in action, but safer and more convenient to use.
Portal "Eternal youth" http://vechnayamolodost.ru25.08.2010