The human body relies on a series of chemicals to carry out all of its essential functions. Neurotransmitters and hormones are the chemicals which control every system and process within the body. Norepinephrine is both a neurotransmitter and a hormone. As a result, its role within the body is essential to normal body and brain function.
Norepinephrine is classified as a catecholamine chemical that plays a significant role in how the body responds to stress. The body’s “fight-or-flight” response is coordinated by both epinephrine (adrenaline) and norepinephrine (noradrenaline). However, noradrenaline is more involved with maintaining normal body functions like heart rate, blood pressure and sugar levels than responding to perceived threats. Norepinephrine is secreted by the adrenal medulla glands, and is produced by the nerve endings in the sympathetic nervous system.
The body’s “flight-or-fight” system is designed to prepare the body for a perceived threat or stressful situation. Norepinephrine assists in this process by increasing blood sugar levels, opening up the bronchial airways, and converting bodily fats to fatty acids. Heart rate and blood pressure increases are also triggered. Norepinephrine secretions coordinate the communications that take place within the sympathetic nervous system. Synaptic nerve endings release this chemical into body. Response signals are transmitted from these nerve endings to other cells. The cells then propagate the signal from one to the other.
Norepinephrine’s effects on the brain involve the areas that regulate attention, sleep, learning and emotions. When released, it stimulates the emotional and cognitive centers of the brain. When produced in normal amounts, it can create a sense of well-being, as well as euphoria. Norepinephrine is manufactured from dopamine–another neurotransmitter--and the amino acid, tyrosine. Certain foods like almonds, apples, nuts and grains provide the building-block materials needed by the brain to manufacture norepinephrine.
Norepinephrine’s role as a brain and body stimulant requires a certain level of this chemical to be present to achieve normal mental and emotional function. Its primary mechanism is that of arousal. When low levels of norepinephrine are present, depression symptoms may result. Individuals may feel less alert and experience low energy levels. Memory problems and a loss of interest in everyday activities may also result. A number of medications used to treat depression symptoms are designed to target both dopamine and norepinephrine levels to restore a normal chemical balance within the brain.
As low levels of norepinephrine can produce a depressed effect, high levels of this chemical can create a continuous feeling of hyperarousal. Feelings of hyperarousal can cause a person to experience prolonged bouts of anxiety, restlessness and irritability. Physical effects may also be present in the form of muscle tension, jumpiness and an increased heartbeat. When this condition persists, psychological anxiety disorders can develop. In cases where unusually high levels of norepinephrine are present, an individual can experience a full-blown panic attack. The symptoms experienced in a panic attack–sweating, hyperventilating, rapid heartbeat and tremor--are the result of norepinephrine’s effects on brain and body processes.