Neuropeptide Y – or just “NPY” for short – is a compound with a wide variety of potential effects on the body and brain. It has been suggested to play a key role in stress, pain, and anxiety, among many other interesting functions. However, its mechanisms of action appear to be quite complex, and science is still actively figuring out exactly how this neuropeptide might be related to various aspects of physiological and psychological health. Read on to learn more about what NPY is, how it might work, some of its purported roles throughout the body, and some of the lifestyle and other factors that may influence a person’s levels of this interesting compound! What is a Neuropeptide?
Neuropeptides are protein-like molecules (“ peptides ”) used by neurons to communicate with other neurons. In this respect, they are quite similar in function to neurotransmitters (such as serotonin , dopamine , and norepinephrine ), in that they act as the “chemical messengers” that allow one neuron to influence the activity of another.
Also similar to neurotransmitters, neuropeptides travel in “packets” called vesicles . These vesicles are packed and moved around ( trafficked ) through a neuron until a particular signal is given to release them. Once released, neuropeptides drift throughout the synapse or the brain until they are received by another cell, where they exert their effect on neural activity [ 1 ].
In other words, both neurotransmitters and neuropeptides are part of what allows neurons to “communicate” with each other in order to pass along signals and process information – which is obviously what allows the brain to function as a coherent whole, rather than just being a bunch of isolated cells.
However, there are two main differences between neuropeptides and neurotransmitters. The first difference is that neuropeptides are generally much larger molecules than neurotransmitters. The second – and more important – difference is that neurotransmitters are relatively fast-acting, and produce a very rapid and short-lived response in the neuron that receives them; in contrast, neuropeptides are much slower-acting, and produce significantly longer or more sustained effects on the receiving neuron [ 2 , 3 ].
It is also important to note that the label “ neuropeptide ” is contextual: for example, there are many hormones that act on the brain, which is why they are sometimes referred to as neuropeptides or neuropeptide hormones . In other words, these two labels are not mutually exclusive: a compound can be referred to as a hormone (or any other type of compound) when it is acting on the body in general, and can also be referred to as a neuropeptide when discussing its actions on the brain, specifically.
A few examples of neuropeptides include [ 4 ]: What Is Neuropeptide Y?
Neuropeptide Y – or just “NPY” for short – is a specific neuropeptide that has been found in many different parts of the brain, including the hypothalamus , cerebral cortex, and spinal cord [ 5 ].
While NPY appears to be present throughout many regions of the brain, NPY is predominantly found throughout the sympathetic nervous system. This has led some researchers to speculate that NPY’s main role might pertain to the primary functions of the sympathetic nervous system, such as the “ fight-or-flight ” response [ 5 ].
However, NPY is also found elsewhere, such as the cardiac non-sympathetic and parasympathetic nerve fibers [ 5 ]. This probably indicates that NPY has a number of different key roles – and which one it plays at any given time might depend on exactly where it is in the body and brain.
In any case, it is clear that much more research will be needed to tease out all the different functions of NPY throughout the brain and nervous system as a whole. NPY Receptors
NPY shares a similar molecular structure with other neuropeptides, such as peptide YY ( PYY ) and pancreatic polypeptide (PP) [ 6 ]. All three peptides are therefore considered to belong to a single “family” of neuropeptides due to their overall similarities.
There are 5 specific receptor subtypes that carry out functions related to NPY, called ‘Y1’ through ‘Y5’.
However, relatively little is currently known about the subtle differences that exist among these five specific subtypes of receptors. Much of what is currently known pertains to the ‘Y2’ and ‘Y5’ subtypes: The Y2 receptor is a receptor subtype found in the highest concentration in the human brain, and appears to be involved in a diverse range of activities including the regulation of movement, heart, and blood, memory processing, circadian rhythms and release of other neurotransmitters [ 7 ].
The Y5 receptor is a receptor subtype commonly found throughout the hypothalamus , which is believed to be related to eating behavior. However, the Y5 receptor can also be found in the human testes, spleen, and pancreas; this suggests that there are probably many other undiscovered functions of the Y5 receptor [ 8 ].
In the sections below, we will discuss what the latest science currently has to say about some of the potential effects of NPY, and its wider roles in physiological and/or psychological health.
However, it is important to note that while some of these preliminary findings may seem to shed some light on the mechanisms and effects of NPY, the evidence so far is still too weak as a whole to come to any definitive conclusions about its effects on the body and brain, or how relevant it might be when it comes to any specific aspects of health or health conditions.
In other words, these purported effects of NPY should be considered as currently having insufficient evidence to support them – and much more research will still be needed to figure out exactly what effects NPY might have in humans.
With that in mind, let’s continue on to see what the science currently says about this interesting neuropeptide!
Some early evidence from an animal study suggests that NPY may have “sedative” and “ anxiolytic ” (anti-anxiety) effects that may partially counteract some of the physiological […]