Norepinephrine

Norepinephrine is both a neurotransmitter and a hormone that fuels the body's stress response by raising heart rate, releasing glucose, and boosting blood flow to muscles, and it's a key target of several psychiatric medications on the AP Psych exam.

Verified for the 2027 AP Psychology examLast updated June 2026

What is Norepinephrine?

Norepinephrine pulls double duty in your body. As a neurotransmitter, it carries signals between neurons. As a hormone, it travels through your bloodstream to trigger body-wide changes. Either way, its main job is to get you ready for action.

When you're stressed or scared, norepinephrine cranks up your heart rate, dumps glucose (sugar) into your blood for quick energy, and sends more blood to your skeletal muscles so you can run or fight. It's a core player in the fight-or-flight response. Because it influences alertness and mood, norepinephrine is also a target for medications that treat depression, anxiety, and ADHD, which ties it directly to the biological perspective on treatment.

Why Norepinephrine matters in AP Psychology

Norepinephrine shows up in two very different corners of the course. In Unit 2 (Cognition), it's part of neural firing and how chemical messengers move information through your nervous system (topic 2.4). In Unit 8, it returns under treatment of disorders from the biological perspective (topic 8.9), where drugs that adjust its availability help manage real symptoms. That double appearance is the point. The same molecule that explains a basic biology concept early in the course explains how medication works later. Knowing norepinephrine lets you connect the wiring of the brain to the way psychologists actually treat people.

How Norepinephrine connects across the course

Fight-or-Flight Response (Unit 2)

Norepinephrine is one of the chemicals that flips the switch on fight-or-flight. When you sense a threat, it floods your system and produces the racing heart and burst of energy you feel, so think of it as the body's gas pedal in a crisis.

Adrenaline (Unit 2)

Norepinephrine and adrenaline (epinephrine) are chemical cousins that work as a team in the stress response. Adrenaline is the main accelerator, and norepinephrine backs it up, both raising heart rate and prepping your muscles to move.

Antidepressant and ADHD Medications (Unit 8)

Some antidepressants and stimulants like Ritalin work by increasing norepinephrine availability in the brain. This is exactly the biological-perspective logic from topic 8.9, which is that changing a neurotransmitter's levels can change mood, focus, and behavior.

Acetylcholine (Unit 2)

Like norepinephrine, acetylcholine is a neurotransmitter, but it handles different jobs such as muscle movement and memory. Pairing them helps you remember that each neurotransmitter has its own specialty rather than one generic effect.

Is Norepinephrine on the AP Psychology exam?

On multiple-choice questions, norepinephrine usually appears in two ways. First, as a stress-response chemical alongside adrenaline and the fight-or-flight response. Second, as a drug target, where a stem might ask which medication works by increasing the availability of norepinephrine or serotonin in the brain (the answer points toward certain antidepressants). You may also see it tied to stimulant treatments for ADHD. No released FRQ has used the term verbatim, but it fits naturally into a biological-perspective response where you explain how a neurotransmitter or a medication affects behavior. If a free-response prompt asks you to apply a treatment concept, naming norepinephrine and saying what it does is the kind of specific evidence that earns points.

Norepinephrine vs Adrenaline (epinephrine)

These two are easy to mix up because they do similar things and work together in stress. The simple rule: adrenaline (epinephrine) is mainly a hormone released by the adrenal glands and is the headline accelerator of fight-or-flight, while norepinephrine acts as both a neurotransmitter and a hormone and is more tied to alertness and the brain medications in Unit 8.

Key things to remember about Norepinephrine

  • Norepinephrine is both a neurotransmitter and a hormone, so it works inside the brain and travels through the bloodstream to affect the whole body.

  • Its main job is preparing you for action by raising heart rate, releasing glucose, and boosting blood flow to your muscles during the fight-or-flight response.

  • Several antidepressants and stimulant ADHD medications work by increasing norepinephrine availability in the brain, which is the biological perspective on treatment from topic 8.9.

  • Norepinephrine and adrenaline are chemical partners in the stress response, but adrenaline is mainly a hormone while norepinephrine is also a neurotransmitter.

  • The term bridges Unit 2 (neural firing) and Unit 8 (treatment), so it connects basic brain biology to how real psychiatric drugs work.

Frequently asked questions about Norepinephrine

What is norepinephrine in AP Psychology?

Norepinephrine is a chemical that acts as both a neurotransmitter and a hormone, driving the body's stress response by increasing heart rate, releasing glucose for energy, and sending more blood to your muscles.

Is norepinephrine the same as adrenaline?

No, but they're closely related. Adrenaline (epinephrine) is mainly a hormone from the adrenal glands and the lead accelerator in fight-or-flight, while norepinephrine works as both a neurotransmitter and a hormone and is more linked to alertness and the brain medications in Unit 8.

How does norepinephrine relate to depression and ADHD medications?

Some antidepressants and stimulants like Ritalin work by increasing norepinephrine availability in the brain. This is the biological-perspective idea from topic 8.9, where adjusting a neurotransmitter's level can improve mood or focus.

Why does norepinephrine show up in two different AP Psych units?

It appears in Unit 2 as part of neural firing and the stress response, then returns in Unit 8 as a target of psychiatric drugs. Seeing it twice helps you connect basic brain biology to how real treatments work.

Is norepinephrine on the AP Psychology exam?

Yes. It commonly shows up in multiple-choice questions about the stress response and about medications that increase norepinephrine or serotonin in the brain, and it's solid evidence for any biological-perspective free-response answer.