from CBS news
http://www.cbsnews.com/8301-18563_1...of-drugs-could-offer-depression-breakthrough/
"
Jim Staples, 58, has suffered from depression since his twenties.
"I tried to commit suicide, and it wasn't a hearty attempt," Staples says. "It was just screaming out for help." snip
"The medicines that I had been taking over the years, they only work for two to three years and then they just fizzled out," Staples adds.
In depressed patients such as Jim Staples, brain cell communication breaks down. Current medications target a chemical called serotonin to help brain cells talk to each other. But it's present in just five percent of those cells. snip
These new drugs target a different chemical called glutamate, present in 80 percent of brain cells. Researchers believe these new drugs restore the lost communication better than older drugs, which can take months to kick in.
"The exciting part of some of these newer medications is that they might, in fact, produce very rapid antidepressant effects, within hours or days," says Dr. Gerard Sanacora of Yale University, who is leading one of the trials.
The new approach was discovered by accident, when doctors noticed that an anesthesia drug -- ketamine, which targets glutamate -- relieved depression. But it also caused symptoms that mimicked schizophrenia...."
ketamine blocks the nmda receptor at the allosteic site and is a glutamate antagonist
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from wikipedia heres a snip but hey check out the entire wikipedia article...amazing stuff
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tamine is a noncompetitive NMDA receptor (NMDAR) antagonist. More specifically, ketamine binds to the allosteric site of the NMDA receptor, effectively inhibiting its channel. The S(+) and R(-) stereoisomers bind with different affinities: Ki = 3200 and 1100 nM, respectively.[41] NMDAR antagonism effects analgesia by preventing central sensitization in dorsal horn neurons; in other words, ketamine's actions interfere with pain transmission in the spinal cord.[27] Ketamine also inhibits nitric oxide synthase, inhibiting production of nitric oxide, a neurotransmitter involved in pain perception, and hence further contributing to analgesia.[42] Ketamine also interacts with sigma and opioid receptors, but with lower affinity and without significantly contributing to analgesia.[43]
Ketamine also interacts with a host of other receptors to effect analgesia. It blocks voltage-sensitive calcium channels and depressessodium channels, attenuating hyperalgesia; it alters cholinergic neurotransmission, which is implicated in pain mechanisms; and it acts as a noradrenergic and serotonergic uptake inhibitor, which are involved in descending antinociceptive pathways.[27][44]
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very interesting drug.... reminds me of tianeptine that louise was talking about on another thread