May be 'old hat' but if not AJT wants to know about this.
Waverley, Krispy, Dr Don too.

The an[a]esthetic Ketamine [[aka party drug Special-K]] appears to =

alleviate severe depression within hours rather than the weeks to =

months that most antidepressants take.

This is believed to be because traditional antidepressants act on the =

early stages of a multi-stage process, and it takes weeks for the =

effects to "ripple down" the chemical chain to produce the end effect, =

whereas ketamine is believed to act on the end stage of the process by =

directly blocking an NMDA receptor in the brain.

Papers on this subject have been around since about 2000!!! but seem =

to have surfaced again recently, probably as a result of positive =

results in trials.

http://www.google.co.nz/search?hl=3Den&q=3Dketamine+depression&meta=3D
http://www.nimh.nih.gov/press/ketamine.cfm
http://www.clinicaltrials.gov/ct/show/NCT00088699
http://www.forbes.com/forbeslife/health/feeds/hscout/2006/08/07/hscout53422=
9.html
http://www.newscientist.com/article.ns?id=3Ddn9696&feedId=3Donline-news_rss=
20
http://www.biopsychiatry.com/ketaminedep.htm
http://www.newscientist.com/channel/health/mg19325876.600-tackling-depressi=
on-with-ketamine.html
http://www.boston.com/yourlife/health/mental/articles/2006/08/08/drug_may_q=
uickly_lift_depression_study_says/



_______________


Ketamine, an anesthetic also used illegally as the club drug Special =

K, has the power to lift stubborn depression within hours, instead of =

the weeks it typically takes prescription antidepressants to kick in, =

a new federal study suggested yesterday.

______________

    http://www.nimh.nih.gov/press/ketamine.cfm
Ketamine blocks a brain protein called the N-methyl-D-aspartic acid =

(NMDA) receptor. Previous studies have shown that agents that block =

the NMDA receptor reduce depression-like behaviors in animals.

NMDA receptors are critical for receiving the signals of glutamate, a =

brain chemical that enhances the electrical flow among brain cells =

that is required for normal function. Studies indicate that =

dysregulation in glutamate could be among the culprits in depression. =

Using ketamine to block glutamate's actions on the NMDA receptor =

appears to improve function of another brain receptor =97 the AMPA =

receptor =97 that also helps regulate brain cells' electrical flow.

Scientists think the reason current antidepressant medications take =

weeks to work is that they act on targets close to the beginning of a =

series of biochemical reactions that regulate mood. The medications' =

effects then have to trickle down through the rest of the reactions, =

which takes time. Scientists theorize that ketamine skips much of this =

route because its target, the NMDA receptor, is closer to the end of =

the series of reactions in question.

"This may be a key to developing medications that eliminate the weeks =

or months patients have to wait for antidepressant treatments to kick =

in," said lead researcher Carlos A. Zarate Jr., of the NIMH Mood and =

Anxiety Disorders Program.





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