Isn’t it odd how different people react differently to stressful situations? What makes some people highly resilient, able to cope with the stressful situation, and go on with their lives in a functional manner? While others, seem to deteriorate. They are vulnerable to the stressor, that the first group rode through easily. For whatever reason, they are unable to tolerate the situation, and become depressed, anxious, or have Post-Traumatic Stress Disorder. Many times, they become dysfunctional to tasks of every day living, and relationships suffer as well.
Now researchers have reported that the brain yields clues about why some succumb while others prevail. Discovery of resistance mechanisms in mouse brain may lead to help for stress-related mental illness in humans.
In the mouse model, the ability to adapt to stress is driven by a distinctly different molecular mechanism than is the tendency to be overwhelmed by stress. The researchers mapped out the mechanisms -- components of which also are present in the human brain -- that govern both kinds of responses. What they discovered was that some mice are genetically inclined to be vulnerable to stress, while others show a biological resistance. There is a strong hypothesis that the same mechanism if prevalent in human brains as well.
The chemistry observed was the difference in the rate of impulse-firing by cells that make dopamine. Vulnerable mice had excessive rates during stressful situations. However, resistant mice maintained normal rates of firing because of a protective mechanism—a boost in activity of channels that allowed the mineral potassium to flow into the cells, which decreased the firing rates.
The really hopeful portion of these studies was that a compound injected into the vulnerable mice, made them resistant mice. Mice who could not tolerate stress, now amazingly acted as if the stress did not occur. This intervention holds the promise that one day, we could intervene on a very primal level to help those people who suffer with mental illnesses which are incapacitating.
Sources
The National Institute of Mental Health (NIMH)
http://www.nih.gov/news/pr/oct2007/nimh-18.htm
Krishnan V, Han M-H, Graham DL, Berton O, Renthal W, Russo SJ, LaPlant Q, Graham A, Lutter M, Lagace DC, Ghose S, Reister R, Tannous P, Green TA, Neve RL, Chakravarty S, Kumar A, Eisch AJ, Self DW, Lee FS, Tamminga CA, Cooper DC, Gershenfeld HK, Nestler EJ. Susceptibility and Resistance to Social Defeat Are Mediated through Molecular Adaptations in Brain Reward Regions. "Cell", online Oct. 18, 2007.
http://www.cell.com/content/article/abstract?uid=PIIS0092867407012068
del.icio.us
Digg this
