Increasing the concentration of neurotrophin-3 stimulates neuron growth and connectivity.

Current treatments for anxiety disorders, depression and substance abuse issues generally only work for some people and often do not completely alleviate the symptoms. However, researchers at the University of California, Davis, the University of Wisconsin-Madison and the State University of New York Downstate Medical Center have identified a potential new drug target.

In nonhuman primates, the scientists found that increasing the concentration of neurotrophin-3 results in changes in “positional anxiety,” the tendency to perceive many situations as threatening. They initially discovered that molecular alterations occur in the dorsal amygdala of preadolescent rhesus macaques. The dorsal amygdala plays an important role in emotional responses, suggesting that the alterations might contribute to early-life anxiety.

RNA from the dorsal amygdala was sequenced to identify molecules related to dispositional anxiety and dorsal amygdala function, leading to a focus on the growth factor neurotrophin-3. In juvenile rhesus macaques, an altered virus was used to increase the levels of neurotrophin-3 in the dorsal amygdala. The treated macaques experienced a decrease in anxiety-related behaviors, particularly behaviors associated with inhibition. Brain-imaging studies revealed modified activity in the distributed brain regions that contribute to anxiety. In addition, the growth factor was shown to stimulate neuron growth and the establishment of new neural connectivity.

The scientists are currently investigating other potentially interesting molecules identified in their earlier study.