MUTANT MICE MAY HOLD KEY TO HUMAN VIOLENCE: AN EXCESS OF SEROTONIN, A CHEMICAL THAT HELPS REGULATE MOOD AND MENTAL HEALTH, CAUSES MAYHEM — (Portland Press Herald)

Dr. Ann Blake Tracy’s Statement to the FDA, September 13, 2004 describes the study in the article below as follows (see statement):

A study out of the University of Southern California in 1996 looked at a group of mutant mice in an experiment that had gone terribly wrong. These genetically engineered mice were the most violent creatures they had ever witnessed. They were born lacking the MAO-A enzyme that metabolizes serotonin. As a result their brains were awash in serotonin. This excess serotonin is what the researchers determined was the cause for this extreme violence. Antidepressants produce the same end result as they inhibit the metabolism of serotonin.

Original article no longer available

Portland Press Herald

Jean Chen Shih

August 1, 1996

The scientist grabs Mutant 9 by the tail, lifts the mouse out of its cage, and lowers it into another, identical container, the reeking, sawdust-floored home of Mutant 4.
Blind and jittery, the mice are freaks of nature, products of a genetic engineering experiment that did not go exactly as planned. But, oddly, their encounter in this fifth-floor laboratory at the University of Southern California School of Pharmacy may reveal something vital about human nature.

They square off, sniffing furiously, then inch closer. Within seconds, 9 corners 4. And then they dive at each another – a rolling, squeaking, clawing gray blur.
Jean Chen Shih, a USC biochemist, startled by the attack even though she was expecting it. “Normal mice fight also, but not so rapidly as these,” Shih says.
By any measure, the mice, called Tg8, are among the most aggressive in captivity.

This odd little spectacle is part of the quest for answers to the violence clawing at America’s soul. A Tg8 is born with its brain awash in an excess of serotonin, a neurotransmitter chemical that helps regulate mood and mental health, and Shih and her co-workers believe that that excess greatly contributes to the mouse’s fierce temper.

To be sure, a brawl between blind mice in an ivory tower is a far cry from the mayhem and brutality perfected by such brainy animals as ourselves. But the work does appear to touch on human experience: The Tg8’s cardinal biochemical defect was originally discovered in numerous related Dutchmen who committed arson, attempted rape and assault.

The Tg8 mice are the first laboratory animals to share both the biochemical defect and the behavior observed in a pedigree of violent criminals. In that sense, the mice are an important new tool for probing the physiology of running amok.

Scientists at the Pasteur Institute near Paris accidentally created the Tg8 mouse strain two years ago. Olivier Cases and colleagues were trying to develop a novel gene therapy by injecting a one-celled embryo of a special lab strain of blind mice with a shred of foreign DNA. But instead of resulting in a “new” mouse pup with abolstered immune system, the experiment led to a strain of male mice with a really bad temper.

The first indicator of that ill nature was painfully obvious: The mice nipped the researchers’ fingers. When caged together, male Tg8s – the Tg is for “transgenic” – tore each other apart.

Those traits may be reminiscent of any number of men, but the French researchers were put in mind of certain Dutch males in one extended family described in the medical literature. Over four generations, a remarkable number of those males were accused or convicted of rape, assault and arson, leading local psychologists as well as law enforcement authorities to watch them very closely.

After much study, Dutch scientists reported a finding in 1993 that, they believed, helped explain the males’ behavior: They were missing an enzyme called monoamine oxidase A, or MAO-A, which breaks down a variety of neurotransmitters, including serotonin.

Copyright Portland Newspapers Aug 11, 1996
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