SAN DIEGO-- A repetitive drop in blood oxygen levels in newborn rats, similar to that caused by apnea (brief pauses in breathing) in some human infants, is followed by a long-lasting reduction in the release of the brain neurotransmitter dopamine, according to an Emory University research study. Because dopamine promotes attention, learning, memory and a variety of higher cognitive functions, the researchers believe repetitive apnea during neonatal development may be one factor leading to the development of attention deficit hyperactivity disorder (ADHD). This research will be reported at the Society for Neuroscience annual meeting in San Diego on October 24 by Glenda Keating, PhD, and Michael Decker, PhD, of the Department of Neurology at Emory University's School of Medicine. The research was funded by the National Heart Lung and Blood Institute and conducted by the Program in Sleep Medicine and the Department of Neurology at Emory University.

Apnea of prematurity occurs in up to 85 percent of all prematurely born human infants, and obstructive sleep apnea occurs in 3 to 27 percent of all children. Data from previous studies suggests that diminished release of brain dopamine may be responsible for behaviors such as impulsiveness and distractibility, reduced self control, and impaired learning, which are hallmark traits associated with ADHD. Previous studies in Dr. Decker's laboratory at Emory have shown that newborn rats who experience repetitive drops in blood oxygen levels go on to develop behavioral traits similar to those seen in humans with ADHD. This is the first time, however, that researchers have linked repetitive reductions in blood oxygen levels during a period of critical brain development to long-lasting deficiencies in release of dopamine specifically within the striatum, which is one of the brain regions important in modulating behavior, learning and memory.

The scientists exposed newborn rats from 7 to 11 days old to either 20-sec
'"/>

Contact: Holly Korschun
hkorsch@emory.edu
404-727-3990
Emory University Health Sciences Center
24-Oct-2004

Page: 1 2 3
Related biology news :

1. High blood pressure, low energy -- a recipe for heart failure
2. Brain blood flow gives clues to treating depression
3. Study finds gender differences in renal and other genes contributing to blood pressure
4. Study suggests estrogen deficiency can lead to obesity-induced high blood pressure after menopause
5. Research aims to identify markers for menopausal women at risk for deadly blood clot
6. Teamwork between 2 key proteins necessary for normal development and regulation of red blood cells
7. A low expression of MX2 gene exists in the white blood cells of narcoleptics
8. How a pain in the neck could be bad for your blood pressure
9. Penn researchers discover pathway that eliminates genetic defects in red blood cells
10. U-M team identifies gene that regulates blood-forming fetal stem cells
11. MicroRNA works with Ago2 protein to regulate blood cell development