April 23, 2009
JOHNSON CITY The biological mechanisms of the way in which chronic stress contributes to the development of clinical depression is the focus of a new research study at East Tennessee State Universitys James H. Quillen College of Medicine funded by a $1.15 million National Institutes of Health grant.
Dr. Meng-Yang Zhu, an ETSU associate professor of pharmacology and lead investigator in the study, believes a critical link in this process is the ability to control the levels of norepinephrine and other chemical neurotransmitters in the brain known as monoamines.
Many drugs that are effective in treating depression elevate the levels of norepinephrine in active sites of the brain, Zhu said. These antidepressant drugs are able to accomplish this by blocking a protein called the norepinephrine transporter that removes norepinephrine from active sites in the brain.
Through his research, Zhu has discovered that certain specific hormones released in the body during chronic stress will actually increase the expression of the norepinephrine transporter, which, in turn, may boost the removal of norepinephrine from active sites in the brain.
And this, we believe, leads to the development of depression, he concluded.
Zhus goal is to understand the molecular mechanisms underlying the ability of stress hormones to regulate the expression of the norepinephrine transporter. He believes this work may help identify additional targets in the brain for the development of newer approaches for treating behavioral consequences of stress and preventing stress-related disorders such as depression.
Dr. Gregory Ordway, ETSU professor and chair of pharmacology, is a co-investigator in this project.