Epinephrine [BSA]

Epinephrine (aka Adrenaline) is a neurotransmitter and a hormone. It's involved in the body's "fight or flight" response. The pills of epinephrine also are available as drugs for the treatment of lethal illnesses. Epinephrine is geared up to kick into gear during stress or danger by getting the body ready for "fight or flight" mode. That adrenaline rush is what primes the body for "fight or flight". Epinephrine is made and released into the blood from norepinephrine in the adrenal glands, caps of glands that sit above the two kidneys of the body. As a central nervous system neurotransmitter, it's a chemical messenger that transports nerve impulses across nerve endings to another nerve cell, muscle cell or gland cell. Epinephrine is part of the sympathetic nervous system — the body's emergency mechanism for determining to "fight or flight" from a threat.

Figure 1. Schematic illustration of adrenaline activation of the carotid body (CB) during hypoglycemia.(Aldossary HS, et al. 2020)

Adrenaline as a neurotransmitter is a smaller part of its function. The main role of adrenaline is that it plays a regulatory role as a hormone in metabolism, attention, focus, panic and excitement. Studies have shown that abnormal adrenaline levels are often associated with sleep disorders, anxiety, high blood pressure and decreased immunity. Therefore, adrenaline is released in response to stress. This reaction causes many changes in people's bodies, which is called the "fight or flight response". The fight or flight response is how people's bodies react to stressful situations, such as the need to escape danger (away from a growling dog) or face tension or fear (giving a speech at school or work, participating in adventure activities and extreme sports). The term comes from the choice our ancestors faced when faced with dangerous situations, which was to stay and fight or flee to safety. In the fight or flight response, we (our own brain) perceive danger, nerves in the brain area called the hypothalamus send a signal to the spinal cord, and the neurotransmitter that transmits the message to the brain's nervous system is norepinephrine. The neurotransmitter goes on to follow up the next organs and tissues, and initiates these fast-acting bodily responses. These body reactions are: Eyes: Pupils open to let in lighter so you can see around you. Skin: Skin becomes white as vessels signal to channel blood away from areas in need of oxygenated blood (muscles, etc) to fight or run. Heart: The heart pumpes harder and faster so more oxygenated blood gets to the vital parts (such as muscles). Blood pressure also rises. Muscles: Muscles get more blood and oxygen so they can react stronger and faster. Liver: Glucose (which is in the liver) is converted to glucose to give you energy. Stomach: Absorption slacks and blood moves from digestive tract to muscles. Respiratory tract: Breathing gets deeper and faster and lungs contract, adding more oxygen to bloodstream. Alertness: Alertness and wisdom increase, and receptivity increases. The neurotransmitter norepinephrine also goes to the adrenal glands, where adrenaline and norepinephrine are released. The hormones circulate in the blood to every system. They now migrate again to the eyes, the heart, the respiratory tract, blood vessels in the skin, and adrenal glands. Epinephrine sets the signalling wheels in motion by attaching to adrenergic receptors on the cell walls. Such "messages" to organs and tissues respond up until threat is gone. Here's a rudimentary account of the flight response. Hormones and neurotransmitters also occupy other nervous systems and organs.

The releasing of adrenalin is an intricate process that depends on various factors: 1. Sympathetic-adrenal medullary system: If there is an emergency or a stress in the body, the brain relays the news to the sympathetic nerves so adrenaline comes flowing from the adrenal medulla. It's the "fight or flight" reaction.2. HPA axis: When stressors become chronic or long term, the hypothalamus releases CHR, and that releases ACTH from the pituitary, which then makes the adrenal cortex release cortisol, producing and releasing adrenaline. 3. Low blood sugar: Blood sugar drops, adrenaline will be released to keep blood sugar balanced. 4. Feedback system: As adrenaline is released it can cause high blood pressure and increased heart rate. They may prevent adrenalin from being pumped out even further, via negative feedback systems. 5. Other factors: Fear, anxiety, excitement — these affects can directly or indirectly stimulate the sympathetic nervous system to pump more adrenaline. What's more, during intense exercise, your body requires more energy and oxygen, so adrenalin will release even more of this to boost heart rate and blood pressure and supply your muscles with more blood and oxygen. Furthermore, on the cellular level, adrenalin receptor activation, G protein and primary enzyme activity are all essential for adrenaline synthesis and regulation.

Adrenaline
1-(3,4-Dihydroxyphenyl)-2-methylaminoethanol
C8H11NO3
4-(1-Hydroxy-2-methylaminoethyl)-1,2-benzenediol
(±)-3,4-dihydroxy-α-((methylamino)methyl)benzyl alcohol