The Chemistry of Pain

Introduction

Composition of ...

C8H11NO2=dopamine

C99H155N31O23=dynorphins

Met-enkephalin= C27H35N5O7S

Leu-enkephalin= C28H37N5O7

Serotonin= C10H12N2O

norepinephrine= C8H11NO3

Glutamate= C5H8NO4-

Substance P= C63H98N18O13S

Neurokinin A= C50H80N14O14S

Main Chemicals, Compounds, Components

Glutamate (C5H8NO4-), which is found in the cell membranes of neurons throughout the nervous system and the most abundant neurotransmitter in the brain, is responsible for many things, such as brain development, memory, learning, and of course nociception (pain processing). This neurotransmitter, when involved with nociception, is found at the synapses along the nerves that consist of the pain processing path. By binding with its protein receptors found only on specific cells, it carries the signal known as pain to the CNS (Central Nervous System) and up to the brain.

Substance P (C63H98N18O13S) is a tachykinin neuropeptide involved with the transmission of pain. As with Glutamate, it is found within the synapses along the nerves that consist of the pain processing path. During nociception, it binds with its receptor, Neurokinin 1 (found on the neurons in the area of the spine known as the dorsal horn) to transmit the signal of pain to the brain. In addition, it can cause the release of substances, such as bradykinin (causes a drop in blood pressure), histamine (induces inflammatory response), and serotonin (starts wound healing).

Chemistry's Role

Both components (substance P and Glutamate) are naturally occurring neurotransmitters that are found throughout the CNS. The final product (pain) is a result of not only the amounts of both of these neurotransmitters, but the overall effects. The whole process of pain acts kind of like a chemical reaction, as several products are created throughout the nociceptive process. When a stimuli acts upon a nociceptive neuron, it sends a message through the nerves. At the synapses of these nerves, neurotransmitters and neuropeptides await, and transmit the signal to their corresponding receptors. Substance P, for example, binds to neurokinin 1 to transmit the signal. During that process, it causes a release of bradykinin, histamine, and serotonin. Bradykinin causes a drop in blood pressure, which is an involuntary response to pain. Histamine causes the inflammatory response, which increases permeability to white blood cells and other proteins to prevent or fight infection. Serotonin is released by platelets involved in a clot, which constricts blood vessels to maintain homeostasis, and is also a growth factor, giving it a role in wound healing. When the signal reaches the thalamus of the brain, it goes to the prefrontal cortex, hypothalamus, and amygdala for further processing. In addition, the brain releases dopamine into the basal ganglia and nucleus accumbens. The basal ganglia helps process the pain itself, while the nucleus accumbens affects the emotional experience. When the brain fully processes the information it has received, it generates a response, often a reflex of some sort to withdraw oneself from the painful situation and helps them learn to avoid it in the future. Finally, the brain releases various chemicals, such as Serotonin, norepinepherine, endorphins, and enkephalins to reduce the pain and start the healing process.

Background Research

Overall, pain is the distressing feeling one gets when a type of tissue is damaged, and is a symptom of many medical ailments. You might think that life without pain would be much better than the life you currently lead. Well think again. Pain is one of the body’s defense mechanisms and is vital to survival. It triggers a response that is designed to force one to withdraw from the danger, protect the affected area until completely healed, and avoid similar predicaments in the future. In fact, those who are insensitive to pain have shorter life expectancies than those who aren’t. The best assessment of pain does in fact come from the person that is experiencing the pain, and their knowledge of the events that resulted in pain, location of pain, and intensity can be vitally crucial to revealing the actual medical ailment occurring in the body.

Genes also play an important role in how sensitive to pain a person is. Now there are a lot of genes that work in several different combos to determine how sensitive one is, but there are a couple major ones. The TrpV1 gene is responsible for sensitivity towards temperature related pain. In addition, the COMT gene plays an important role in sensitivity. The less active that gene is, the less sensitive one is to pain. Finally, different genes produce the different substances involved in pain. For example, the TAC1 gene is involved in the production of Substance P.

Resources

https://www.sciencenewsforstudents.org/article/owww-science-pain

Genes involved with pain sensitivity

https://www.mentalhelp.net/articles/what-causes-pain/

Areas of the CNS where pain signals are sent through

Types of nerves involved with pain transmission

Chemicals, neurotransmitters and peptides involved

http://webspace.ship.edu/cgboer/pain.html

Types of Nociceptors

What parts of the body produce certain chemicals

Parts of the brain involved

Chemicals involved in pain reduction

http://www.wisegeek.com/what-is-substance-p.htm

General information on Substance P

http://thebrain.mcgill.ca/flash/i/i_03/i_03_m/i_03_m_dou/i_03_m_dou.html

Substance P’s and glutamates role in pain transmission

Location of neurotransmitters and peptides

Products of Substance P/Neurokinin 1 reaction

Chemicals released that increase sensitivity

https://www.reference.com/science/part-brain-registers-pain-34f99c8440531d3d

Parts of the brain involved with pain processing

http://healthyeating.sfgate.com/glutamate-pain-8891.html

Information on glutamate

https://en.wikipedia.org/wiki/Glutamate_receptor

Location of glutamate

http://neurotransporter.org/glutamate.html

Glutamate and its reactions with its receptors

https://www.sciencedaily.com/releases/2006/10/061019094148.htm

Dopamine’s role in pain processing

http://www.medicalnewstoday.com/articles/145750.php

Types of pain

https://pubchem.ncbi.nlm.nih.gov/compound/dopamine#section=Top

Chemical formulas of dynorphins and dopamine

https://en.wikipedia.org/wiki/Pain

General information/definition of pain

https://pubchem.ncbi.nlm.nih.gov/compound/439260

Chemical formula of norepinephrine

https://en.wikipedia.org/wiki/Neurokinin_A

Chemical formula of Neurokinin A

https://en.wikipedia.org/wiki/Tachykinin_peptides

Tachykinin peptides and genes that produce them

https://en.wikipedia.org/wiki/Substance_P

Chemical formula of Substance P

https://en.wikipedia.org/wiki/Met-enkephalin

Chemical formula of Met-enkephalin

https://en.wikipedia.org/wiki/Serotonin

Chemical formula of Serotonin

Potential healing role in Serotonin

https://en.wikipedia.org/wiki/Glutamate_(neurotransmitter)

Chemical formula of Glutamate

https://en.wikipedia.org/wiki/Leu-enkephalin

Chemical formula of Leu-enkephalin

https://en.wikipedia.org/wiki/Bradykinin

General information on Bradykinin

https://en.wikipedia.org/wiki/Histamine

General information on histamine

\https://en.wikipedia.org/wiki/TAC1

General information on TAC1 gene

About the Author

Caleb Johnson is a Junior at Billings Senior High School. Aside from being a highly accomplished student, he is heavily involved in the wrestling team based at the school. He looks to expand his knowledge in various sciences, and hopes one day to go to college to learn to be a Physical Therapist or Sports Trainer.