New studies zero in on roots of depression and why ketamine reverses it [arstechnica.com]
[There's] been significant progress in unravelling the confusion over ketamine, with researchers identifying a ketamine derivative [arstechnica.com] that tackles depression with far fewer side effects. And this week, a team of researchers at China's Zhejiang University announced that they've figured out where in the brain ketamine acts when it blocks depression, a finding that gives us significant insights into the biology of the disorder.
The new studies rely on the work of a number of other labs, which have identified a specific structure deep in the brain that's associated with depression. Called the lateral habenula [wikipedia.org], it's been associated with a variety of activities, the most relevant of which seems to be the processing of unpleasant outcomes and punishment. Electrodes implanted there have been used to relieve depression in at least one instance.
To test whether this might be the site of ketamine's activity, one team of researchers infused the drug directly into the lateral habenula of rats with depression-like symptoms; it blocked them. So did a separate chemical that inhibits the same proteins that ketamine acts on. Tracking the activity in the area, the researchers were able to show that there are bursts of activity in rats with symptoms of depression that are absent in healthy rats. The drugs that blocked depression suppressed these bursts.
Ketamine blocks bursting in the lateral habenula to rapidly relieve depression [nature.com] (DOI: 10.1038/nature25509) (DX [doi.org])
Astroglial Kir4.1 in the lateral habenula drives neuronal bursts in depression [nature.com] (DOI: 10.1038/nature25752) (DX [doi.org])
Related: FDA Designates MDMA as a "Breakthrough Therapy" for PTSD; Approves Phase 3 Trials [soylentnews.org]
Study Suggests Psilocybin "Resets" the Brains of Depressed People [soylentnews.org]
Ketamine Reduces Suicidal Thoughts in Depressed Patients [soylentnews.org]