Vomiting
Cortisol plays a vital role in regulating vomiting. Nausea and vomiting are controlled by a part of the brain called the area postrema. The area postrema is located outside of the blood-brain barrier. It’s thought to be responsible for sensing toxins in the bloodstream. When toxins are detected, the area postrema signals the brain to stimulate vomiting to get rid of the toxin.
Cortisol works on the area postrema to inhibit vomiting via two different mechanisms. First, cortisol suppresses the activity of neurotransmitters, such as dopamine and serotonin, in signaling vomiting. Second, cortisol increases the activity of GABA, a neurotransmitter that inhibits vomiting. Together, these actions decrease the likelihood of vomiting in response to stress or toxins.
The implications of this are far-reaching. For instance, chemotherapy drugs are designed to kill cancer cells. However, they can also damage healthy cells along the way. One of these side effects is nausea and vomiting, which can be pretty severe. However, because low cortisol levels play a role in these side effects, doctors can mitigate them by giving patients drugs that increase cortisol levels, like dexamethasone. This can help reduce nausea and vomiting during chemotherapy treatments and make them more tolerable for patients.
