Bipolar Disorder Linked To Mitochondrial Dysfunction In Brain Cells

A team of Japanese scientists says it has confirmed a possible link between mitochondrial dysfunction in brain nerve cells and bipolar disorder. The team, which includes scientists at the RIKEN Brain Science Institute based in Wako, Saitama Prefecture, published their findings in the online edition of the US scientific journal Molecular Psychiatry on Tuesday.

There are different hypotheses on the cause of bipolar disorder, with some indicating the involvement of neurotransmitters, but the disease's exact mechanism is unknown. Bipolar disorder, also known as manic-depressive disorder, is characterised by recurrent depressive and manic phases.

In their experiment, the team created a mouse whose mitochondria in brain nerve cells were set to dysfunction through genetic engineering.

Normal mice became active in the dark and stopped their activity as it turned brighter, but the disabled mice continued to be active in the bright environment for a while, showing insomnia-like symptoms seen among bipolar patients. The team has long pointed out the link between mitochondrial dysfunction and bipolar disorder. "There is a possibility to help resolve the disease's mechanism and to develop new drugs,'" said the team's leader, Tadafumi Kato.

http://www.medicalnewstoday.com/healthnews.php?newsid=41906

More on the mice from Molecular Psychiatry

The mutant mice exhibited characteristic behavioral phenotypes, a distorted day–night rhythm and a robust periodic activity pattern associated with estrous cycle. These abnormal behaviors resembling mood disorder were worsened by tricyclic antidepressant treatment and improved by lithium, a mood stabilizer.

We also observed antidepressant-induced mania-like behavior and long-lasting irregularity of activity in some mutant animals. Our data suggest that accumulation of mtDNA defects in brain caused mood disorder-like mental symptoms with similar treatment responses to bipolar disorder.

These findings are compatible with the mitochondrial dysfunction hypothesis of bipolar disorder.

http://www.nature.com/mp/journal/vaop/ncurrent/abs/4001824a.html

I knew there was a sexist side to this research. Psychology has been a patriarchal science since Freud and it can't do anything but work to keep women disadvantaged and second class. :sarcasm:

the sarcasm tag didn't register on me, and i was afraid :scared:

It's because the mother screamed during the delivery!!1!1!

study. But why did it have to be done in Wako?

Bipolar disorder has other genetic components, too. So ya can't just blame the moms!

It's a damn complicated set of conditions.

BMJ has a literature review online that's a little dated (1999) but very thorough. It suggests that at least these hereditary mechanisms are involved:

Locus heterogeneity
Allelic heterogeneity
Epistasis
Dynamic mutation
Imprinting
Mitochondrial inheritance

http://jmg.bmjjournals.com/cgi/content/full/36/8/585?ijkey=915f1da3f76022bce1c33c72d97856cff8e96364

More recently, a specific locus has been implicated:

Scientists Identify A Bipolar Risk Gene, It Is Called FAT
Jan 16, 2006

A collaboration, led by scientists at the Garvan Institute of Medical Research and the University of New South Wales (UNSW) in Sydney, has discovered the first risk gene specifically for bipolar disorder, also known as manic-depressive illness. This means that people who have a particular form of this gene are twice as likely to develop the disease.

Lead author, Dr Ian Blair, says: "We are the first group in the world to take a multi-faceted approach to identify a bipolar risk gene - we used a number of families, unrelated patients, and therapeutic drug mouse models. Each of these three lines of investigation led us to a gene called FAT."

Contributing author Professor Phil Mitchell, Head of Psychiatry at UNSW, says: "Over the last twenty years we have collected blood samples from 67 families right across Australia. This amounts to hundreds of family members (904), some of whom are spread across four generations. This was a strong starting point in our hunt for a Bipolar gene."

"We know that the FAT gene codes for a protein that is involved in connecting brain cells together, what we need to do now is find out exactly how it contributes to the increased risk of bipolar disorder," explains Dr Blair.

http://www.medicalnewstoday.com/medicalnews.php?newsid=36162