Neuropeptides are low–molecular-weight protein molecules that mediate exceptionally important functions in the brains of all organisms. It is well documented that neuropeptides play a role in a wide range of physiological behaviors, including sleep and wakefulness, reproduction, hunger, as well as learning.
Neuropeptides are present in the brain as precursor molecules that become biologically active with the aid of enzymes, while the execution of their functions requires their binding to a receptor—a complementary protein structure located on the surface of cells. In other words, the message conveyed by neuropeptides is understood by the recipient cell when they bind to the appropriate receptor. Neuropeptide receptors currently constitute important targets of neuropsychiatric therapies, including recently approved medications for weight loss.
Nerve cells, or neurons, communicate through synapses, namely regions of close proximity between specialized terminals of two cells. The message takes the form of electrical impulses, which are emitted by one cell and received by another. Indeed, maps of brain synapses of various organisms, including humans, now exist and are referred to as connectomes, from the verb “connect.”
This electrical communication through synapses, however, is not the sole mode of communication among the brain’s nerve cells. According to the scientific journals Neuron and Nature, the brain also possesses a network of chemical communication that utilizes neuropeptides, whose role had not previously been fully appreciated. In reality, they were considered auxiliary facilitators of communication rather than central mediators, as has emerged from recent scientific research.
Suspecting that neuropeptides were responsible for the observed discrepancies, American researchers created genetically modified experimental animals lacking a key protein essential for neuropeptidergic communication. They found that attempts to activate certain neurons—previously successful using a photosensitive protein—were unsuccessful. Their findings demonstrated that neuropeptidergic communication directly activates nerve cells and that neuropeptides are not merely auxiliary components of electrical communication.
The brain is therefore more complex, as it utilizes two forms of cellular communication that cooperate harmoniously: one form involves synaptic communication, while the other occurs through the diffusion of neuropeptides to distant sites. Scientists have termed this latter mode the “Wi-Fi of the brain,” in order to distinguish it from the “wired” synaptic communication.
Konstantinos Kouskoukis
Professor of Dermatology – Lawyer
B’ Vice President GDHI
President Hellenic Academy of Thermal Medicine
President World Academy of Chinese & Complimentary Medicine