Noradrenaline is a neurotransmitter and a catecholamine-type hormone that is manufactured as a drug and produced naturally in the human body. Also called norepinephrine, especially by those in the medical field, this hormone acts on the parts of the brain involved with responsiveness and fear. This neurotransmitter is released into the blood from the adrenal medulla and from nerves called adrenergic nerves. As a drug, control of the noradrenaline catecholamine is commonly used to treat low blood pressure and chronic depression.
Like other neurotransmitters, the noradrenaline chemical triggers a chain of neurons when the body needs to spring into action. When the body needs to react quickly to a stressor, this neurotransmitter increases blood pressure and heart rate, and gets the muscles ready to escape or fight. Too little of this chemical in the body can cause a person to become lethargic and sleepy. Those with low levels of noradrenaline generally have difficulty staying awake, concentrating, and paying attention to tasks. High levels of this chemical in the body can mirror symptoms of overdose, including nervousness, racing thoughts, cold hands and feet, and high blood pressure.
Neurotransmitters are chemicals released by neurons into the synapses — the space between nerves. When released, this chemical binds to neurotransmitter-receiving receptors to trigger a response in the next adrenergic nerve in the chain. Nerves that function as adrenergic nerves act on noradrenaline and related neurotransmitters. Adrenergic neurons and neurotransmitters are present throughout the body and predominantly control involuntary processes that keep the body alive, such as heart rate and breathing.
Noradrenaline is one of a class of hormones called catecholamines that regulate the body's response to stress. Other catecholamines include epinephrine, which is also called adrenaline, and dopamine. Hormones related to adrenaline are implicated in the body's fight-or-flight response mechanisms that trigger when faced with a threat. Catecholamines control stress response and reaction, so these types of hormones are often called stress hormones.
For patients diagnosed with chronic depression caused by an adrenergic deficiency, doctors sometimes prescribe noradrenaline or drugs that control neurotransmitter levels and affect the body's reaction to the chemical. Drugs that increase this neurotransmitter hormone in the body include brand-name drugs Adderall™, Ritalin™, and Dexedrine™. Levophed™ is the brand-name version of noradrenaline, which can be administered orally or intravenously. Side effects of the use of medicines affecting this hormone can include headaches, hiccups, heart attack, or high blood pressure. This drug is not recommended for children.