Neuropeptide Y (NPY) is a 36-amino-acid neuropeptide found abundantly in the brain and autonomic nervous system. It is one of the most widely distributed neuropeptides in the central nervous system and plays major roles in:
- Appetite and energy balance
- Stress response
- Anxiety regulation
- Blood pressure and cardiovascular function
NPY is considered a “survival peptide” because it helps the body adapt to stress and conserve energy during times of scarcity or trauma.
🧠 Where Is NPY Found?
- Central nervous system: Especially in the hypothalamus, amygdala, and brainstem
- Autonomic nervous system: Co-released with norepinephrine from sympathetic nerves
- Peripheral tissues: Heart, gastrointestinal tract, and fat tissue
🔬 What Does NPY Do?
🔹 1. Regulates Appetite
- Strongly stimulates hunger (especially for carbohydrates)
- Increases food intake, particularly under stress
- Promotes fat storage and reduces energy expenditure
- Elevated in conditions of fasting or caloric restriction
🔹 2. Modulates Stress and Anxiety
- Reduces anxiety-like behaviors and promotes resilience
- May have a calming effect under chronic stress
- Interacts with the HPA axis (hypothalamic-pituitary-adrenal axis)
🔹 3. Influences Blood Pressure and Heart Function
- Causes vasoconstriction (tightening of blood vessels)
- Regulates heart rate and blood flow
- Works alongside norepinephrine in the sympathetic nervous system
🔹 4. Other Roles
- Modulates circadian rhythms
- Affects memory and learning
- Influences bone formation and reproductive hormones
📈 When Is NPY Increased?
- Fasting or starvation
- Chronic stress
- Sleep deprivation
- High-fat or high-sugar diets
- Some psychiatric conditions, like PTSD or depression
🧪 Medical Interest in NPY
Researchers are studying NPY for its potential role in:
- Obesity (targeting NPY may help control appetite)
- PTSD and anxiety disorders (NPY may promote resilience to trauma)
- Hypertension (due to its vascular effects)
- Metabolic syndrome and insulin resistance
🎯 NPY Receptors
NPY acts through several Y receptors (Y1, Y2, Y4, Y5):
- Y1 and Y5 → Stimulate appetite
- Y2 → Inhibits release of NPY (negative feedback)
- Y1 and Y2 → Involved in anxiety and cardiovascular regulation
Drugs targeting specific NPY receptors are under investigation.
🧠 Summary Table:
| Feature | Neuropeptide Y (NPY) |
|---|---|
| Type | Neuropeptide (36 amino acids) |
| Produced by | Brain (especially hypothalamus), sympathetic nerves |
| Functions | Stimulates appetite, reduces anxiety, constricts blood vessels |
| Receptors | Y1, Y2, Y4, Y5 (G-protein-coupled receptors) |
| Increased by | Fasting, stress, poor sleep |
| Medical interest | Obesity, PTSD, hypertension, metabolic disorders |