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Enzyme tagged as stress forgetfulness culprit
Randolph Schmid
13 November 2004
HOW many people have come home after a blindingly stressful day and realised they've forgotten some important event or errand?
Well, now at least there's a scientific explanation for the oversight. Stress makes you forgetful.
People going on stage or taking an exam or finding themselves in similarly tough situations already know this, of course.
But a team of researchers has found how it happens, a discovery they say could point the way to better treatments for such illnesses as schizophrenia and bipolar disorder.
Amy Arnsten, of Yale Medical School, says stressful situations in which the individual has no control have been found to activate an enzyme in the brain called protein kinase C, which impairs the short-term memory and other functions in the prefrontal cortex -- the executive-decision part of the brain.
The findings were reported last week in the journal Science.
The PKC enzyme is also active in bipolar disorder and schizophrenia, and Arnsten notes that a first psychotic episode can be precipitated by a stressful situation, such as going away to university for the first time or joining the military.
By affecting that part of the brain, the researchers say, PKC could be a factor in the distractability, impulsiveness and impaired judgment that occurs in those illnesses. The finding that uncontrolled stress activates PKC indicates a possible new direction for treatments -- seeking drugs that inhibit PKC, Arnsten says.
"These new findings may also help us understand the impulsivity and distractability observed in children with lead poisoning," she says. "Very low levels of lead can activate PKC, and this may lead to impaired regulation of behaviour."
The researchers used chemicals to induce stress in rats and monkeys because the stress levels were easily controlled. It was similar to humans exposed to loud noise or panicking before an exam, she says.
"It doesn't have to be traumatic, as long as you feel out of control. Control is the essential factor ... If you are confident, you don't have these problems."
PKC affects a part of the brain that allows abstract reasoning, using working memory that is constantly updated.
"This kind of memory, the ability to concentrate, seems to be impaired when exposed to mild stresses," she says.
Scientists believe the effect evolved as a protective mechanism in the event of danger. "If you're in dangerous conditions it helps to be distractable, to hear every little sound in the woods and react rapidly, instinctively."
Article Source http://theaustralian.com.au report.
Randolph Schmid
13 November 2004
HOW many people have come home after a blindingly stressful day and realised they've forgotten some important event or errand?
Well, now at least there's a scientific explanation for the oversight. Stress makes you forgetful.
People going on stage or taking an exam or finding themselves in similarly tough situations already know this, of course.
But a team of researchers has found how it happens, a discovery they say could point the way to better treatments for such illnesses as schizophrenia and bipolar disorder.
Amy Arnsten, of Yale Medical School, says stressful situations in which the individual has no control have been found to activate an enzyme in the brain called protein kinase C, which impairs the short-term memory and other functions in the prefrontal cortex -- the executive-decision part of the brain.
The findings were reported last week in the journal Science.
The PKC enzyme is also active in bipolar disorder and schizophrenia, and Arnsten notes that a first psychotic episode can be precipitated by a stressful situation, such as going away to university for the first time or joining the military.
By affecting that part of the brain, the researchers say, PKC could be a factor in the distractability, impulsiveness and impaired judgment that occurs in those illnesses. The finding that uncontrolled stress activates PKC indicates a possible new direction for treatments -- seeking drugs that inhibit PKC, Arnsten says.
"These new findings may also help us understand the impulsivity and distractability observed in children with lead poisoning," she says. "Very low levels of lead can activate PKC, and this may lead to impaired regulation of behaviour."
The researchers used chemicals to induce stress in rats and monkeys because the stress levels were easily controlled. It was similar to humans exposed to loud noise or panicking before an exam, she says.
"It doesn't have to be traumatic, as long as you feel out of control. Control is the essential factor ... If you are confident, you don't have these problems."
PKC affects a part of the brain that allows abstract reasoning, using working memory that is constantly updated.
"This kind of memory, the ability to concentrate, seems to be impaired when exposed to mild stresses," she says.
Scientists believe the effect evolved as a protective mechanism in the event of danger. "If you're in dangerous conditions it helps to be distractable, to hear every little sound in the woods and react rapidly, instinctively."
Article Source http://theaustralian.com.au report.
