How is this breastfeeding related? I think it offers more evidence that
practices elevating infant stress (specifically, crying it out) are not
physiologically beneficial to babies.
This is from Medscape. The URL is:
http://pediatrics.medscape.com/reuters/prof/2001/07/07.10/20010709scie003.ht
ml
Neuropeptide Linked to Decreased Cognitive Function After Early-Life Stress
WESTPORT, CT (Reuters Health) Jul 09 - Corticotropin-releasing hormone (CRH)
appears have a role in the mechanisms associated with cognitive impairment
that develops after stress in early life, according to the results of
experiments in an animal model. The findings appear in the July 17th issue
of the Proceedings of the National Academy of Sciences.
"It is well established in humans that individuals who have sustained
chronic stresses, such as separation, neglect or abuse, early in life do not
do well cognitively. However, the mechanism for this has been entirely
unclear," Dr. Tallie Z. Baram of the University of California at Irvine told
Reuters Health.
The dogma, she added, has been that this decline in cognitive function is
mediated through the glucocorticoids. "But we wondered if this was the whole
story, because we knew that when these hormones were given to monkeys in a
nonstressful situation, they do not replicate the effect of stress," Dr.
Baram added.
Therefore, Dr. Baram and colleagues did not look at the classic stress
hormones, but at CRH. The normal function of CRH is to improve the
communication between brain cells during stress. However, "we have
previously shown that too much CRH actually kills brain cells," Dr. Baram
explained.
The researchers infused CRH directly into the brains of baby rats and tested
the rats at 3 months, 6 months, 9 months and at 1 year. "First we tested
their intelligence, using a test that tests learning and memory mediated by
the normal hippocampus. We also sacrificed some of the animals and looked at
the condition of cells in the hippocampus," Dr. Baram said.
"The results were quite surprising," she added. Compared with normal
controls, these animals had a progressive decline in cognitive skills. "We
also saw a progressive loss of cells in the area of the brain where CRH
acts. This proves that CRH can replicate the effects of early life stress."
In another group of animals, the researchers removed the adrenal glands and
gave the rats a fixed low dose of steroids and CRH. "We got exactly the same
result," Dr. Baram said. "You can get these deleterious effects of CRH both
on function and on cell health with or without the presence of high levels
of steroids. So, stress does injure the brain, but it looks like steroids
are not the key player," she added.
"The reason that this is so exciting," Dr. Baram told Reuters Health, "is
that there are specific blockers to CRH, which might be used to protect the
brain after early life stress, or at least intervene in a meaningful way to
protect the brain from the untoward effects of stress."
Proc Natl Acad Sci 2001;98:8856-8861.
-------------------------------------
Warmly,
Anna Swisher
Austin, TX
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