Adrenaline, also known as epinephrine, is a catecholamine that functions as both a neurotransmitter and hormone in humans. Produced by both sympathetic neurons and chromaffin cells in the adrenal medula, adrenaline is released in stressful situations to instigate a fight-or-flight response. Notably, self-administration of syringes of epinephrine are used in movies and video games to acquire super-human reflexes and stamina.
How do scientists know what chemicals do in our bodies? A typical way is to remove the chemical and study the consequences. Patients who suffer the rare disease polyglandular Addison’s disease do not produce adrenaline in stressful situations.
Without adrenaline, the body does not effectively manage blood flow, increase heart rate, and remove neurological limits imposed on muscle strength. However, adrenaline release isn’t the only physiological response to external stress. For instance, glucocorticoid release by the adrenal cortex and an increase in blood sugar also accompany the body’s stress response. Unfortunately, without adrenaline major organs cannot continue to function normally once the stress response is initiated. As a response, patients of polyglandular Addison’s can die instantly when subjected to external stress.
In 2008, 10-year old Jennifer Lloyd gained pseudo-celebrity status for being one of 6 known people diagnosed with polyglandular Addison’s disease. Being unable to modulate blood pressure and electrolyte concentrations in response to stress, Jennifer experienced a number of kidney and gastrointestinal conditions. She has to take large cocktails of medication to alleviate the symptoms. Her parents also note:
When anything particularly good or bad happens, we have to handle it very carefully so it doesn’t surprise Jenny.
Jennifer’s parents claim she lives a fairly typical lifestyle. I think it’s safe to say she won’t end up an adrenaline junkie (quite literally).