By Alice Park
New findings in this animal study could lead to better drugs
Anxiety, and more broadly, stress, is a common part of everyone’s lives, and for good reason: It actually has its roots in a survival mechanism that allows the body to recognize threats and respond accordingly.
But that system can get stuck in overdrive, leading to a constant state of anxiety that can be debilitating and unhealthy. Nearly 20% of the U.S. population has an anxiety disorder. Scientists know what triggers stress and anxiety — psychological and physical events that lead hormones, especially cortisol, to be released — but drugs that tamp down these substances don’t always translate into relief of anxiety symptoms.
Thanks to new research, that may soon change. In an animal study published in the journal Molecular Psychiatry, a team led by Dr. Joseph Majzoub, chief of endocrinology at Boston Children’s Hospital, found that a set of neurons in the brain’s stress control center, the hypothalamus, play a critical role in masterminding the anxiety response.
These neurons control the release cortisol, but they also have connections to other parts of the brain that are involved in behavioral responses to stress, such as an increased heart rate and breath. The scientists genetically engineered mice to be missing a gene that controls the release of cortisol in these neurons and found that not only did the animals have lower levels of stress, but they also showed fewer signs of anxiety in their behavior. These mice, for example, were more adventurous in exploring an elevated gangplank-like maze, and in seeking out exposed areas in their environment, compared to control mice who behaved fearfully, sticking to the periphery of the maze.