New Molecule In Blood-pressure Control System Discovered

The finding could someday play a significant role in the prevention of Sudden Infant Death Syndrome (SIDS) and high blood pressure. According to the National Institutes of Health, SIDS is the leading cause of death in children between 1 month and 1 year of age. About one in three adults in the United States has high blood pressure.

The new discovery was published in a January issue of the Journal of Neurochemistry (vol. 108, pp. 450-464) and released online December 1, 2008.

"Our discovery sheds light on how the nerve supply to the cardiovascular system is established during development," said Agnieszka Balkowiec, M.D., Ph.D., principal investigator, OHSU School of Dentistry assistant professor of integrative biosciences and OHSU School of Medicine adjunct assistant professor of physiology and pharmacology. "Someday we hope to better understand cardiorespiratory developmental disorders such as SIDS."

Changes in blood pressure are signaled to the brain by nerve cells called baroreceptors. The OHSU study shows that baroreceptors make a molecule called Brain-Derived Neurotrophic Factor (BDNF), which belongs to the family of neurotrophins that play a critical role in the development and plasticity of other nerve cells. (Studies suggest that developmental abnormalities in nerve pathways that control the cardiovascular and respiratory system may result in SIDS).

Balkowiec and her team found that the stimulation of baroreceptors, as experienced during an increase in blood pressure, leads to the release of BDNF. The study also discovered that BDNF is present at the central end of baroreceptors in the brainstem.

"In fact, BDNF is likely to play the most important role at the central end of baroreceptors, where they connect to second-order neurons in the blood-pressure control pathway," said Balkowiec. "BDNF has previously been shown to play an important role in establishing neuronal connections in other parts of the nervous system, but this is the first time it has been considered a factor in the blood pressure control system."

Studies under way, in collaboration with Virginia Brooks, Ph.D., OHSU School of Medicine professor of physiology and pharmacology, indicate that levels of BDNF in cardiorespiratory nerve cells increase dramatically when blood pressure rises. This suggests a direct role of BDNF in regulation of blood pressure, said Balkowiec.

Additional study authors include neuroscience graduate student Jessica Martin, B.S., and two OHSU research assistants, Victoria Jenkins, B.A., and Hui-ya Hsieh, B.S.

The study was supported by grants from the American Heart Association and the National Institute's of Health's National Heart, Lung, and Blood Institute.