Neurotransmitters and their Role in Addiction and Substance Abuse

Neurotransmitters are chemical messengers of the body. They are responsible for relaying messages from one nerve cell to another or other cells, like muscle cells. They play essential roles in the very complex functions of the body as well as the seemingly simple ones, ranging from keeping our hearts beating to feeling sensations.

Neurotransmitters are activated when a drug is used. The response of these important messengers to the drug used is what gives the ‘high’ experience connected to drug usage and ultimately causes addiction. The response of neurotransmitters varies from drug to drug, hence the reason the euphoric feeling differs.

What Are Neurotransmitters?

Neurotransmitters are chemical messengers in the body that transmit signals from one nerve cell to another, or to muscles or glands. They carry messages across a tiny gap called a synapse, triggering specific actions like muscle movement, mood regulation, or organ function. These messengers play a crucial role in controlling nearly all bodily and brain functions, including heart rate, breathing, emotions, and learning.

Body functions controlled by Neurotransmitters are:

• Hormone regulation

• Sleep, healing, and aging

• Breathing

• Heart functions and blood pressure

• Muscle movements

• Senses

• Digestion

• Memory and thoughts

What Actions do Neurotransmitters Transmit?

The three possible actions that neurotransmitters transmit are:

• Excitatory action: these Neurotransmitters (norepinephrine, epinephrine, glutamate, etc.) excite the neuron. Hence, the message is ‘fired off’ – implying the message keeps moving to the next cell.
• Inhibitory action: these Neurotransmitters stop the message from moving further, unlike excitatory Neurotransmitters. Examples of Neurotransmitters in this category are: serotonin, glycine, and GABA (Gamma-aminobutyric acid).
• Modulatory action: these neurotransmitters impact how other chemical messengers function. How cells interact at the synapse is adjusted, and they are able to influence a larger number of neurons at once.

What Are The Types of Neurotransmitters?

The Types of Neurotransmitters include excitatory ones like norepinephrine, epinephrine, and glutamate, inhibitory ones like serotonin, glycine, and GABA, and modulatory ones that impact how other chemical messengers function. These regulate various bodily functions from mood to muscle movement.

Here are the types of Neurotransmitters:

Amino acid Neurotransmitters

The majority of the nervous system functions are controlled by Neurotransmitters in this category. They include:

• Glutamate: this excitatory neurotransmitter is the most common in the nervous system, and it is also the brain’s most abundant chemical messenger. How we think, learn, and our memory are significantly influenced by glutamate. If glutamate is not at the level expected, that is an imbalance, and seizures and dementia (among others) are possible outcomes.
• GABA (Gamma-aminobutyric acid): It is an inhibitory Neurotransmitter and the most common in the brain as well as the entire nervous system. The activity of the brain is regulated by GABA, ensuring depression, anxiety, irritability, etc. It’s not a problem.
• Glycine: the spinal cord is a prominent area for this inhibitory neurotransmitter. Metabolism, pain transmission, and hearing are regulated by glycine.

Monoamine Neurotransmitters

They regulate emotion, attention, cognition, and consciousness. Hence, a lot of nervous system disorders are caused by abnormalities of monoamine neurotransmitters. They are commonly affected by many drugs taken by people. These neurotransmitters are:

Serotonin: this inhibitory Neurotransmitter aids in mood, pain, anxiety, sleep, appetite, and sexuality regulation. The imbalance of serotonin is associated with diseases such as depression, anxiety, chronic pain, etc.

Histamine: motivation, feeding behavior, and consciousness are some of the body functions controlled by Histamine. Asthma, multiple sclerosis, mucosal edema, and bronchospasm are all associated with Histamine.

Dopamine: the body’s reward system is impacted by dopamine, hence pleasure, arousal, and learning are affected. Motivation, sleep, concentration, mood, and memory are also enhanced by dopamine.  Several diseases are associated with its dysfunction, including ADHD and bipolar disorder.

Note: it is imperative to mention here that highly addictive drugs like cocaine affect the dopamine system directly.

Epinephrine: it is commonly called adrenaline. It plays a key role in the fight or flight response of the body to stress and fear. It works by raising heart rate, blood pressure, blood sugar, breathing, and blood flow to muscles. Attention and focus are also enhanced, allowing action or reaction to varying stressors. If too much is in the body, epinephrine increases the risk of diabetes, high blood pressure, and heart disease, among others.

Norepinephrine: Norepinephrine, also known as noradrenaline, works like epinephrine. It affects alertness, arousal, attention, and decision-making.

Peptide Neurotransmitters

Endorphins: these chains of amino acids are the body’s natural pain reliever. How we perceive pain is influenced by endorphins. For example, pain is reduced when endorphins are released. It also has a euphoric effect. When low in the body, there is a higher risk for some forms of headache and fibromyalgia.

Acetylcholine

Acetylcholine is an excitatory neurotransmitter and aids the regulation of several important functions in both the central and peripheral nervous systems. The functions include: muscle contractions, libido, motivation, learning, memory, heart rate, gut mobility, and blood pressure.

What are the Roles of Neurotransmitters in Substance Abuse and Addiction?

Having explained what neurotransmitters are and how they work, understanding the roles of neurotransmitters in substance abuse and addiction is easier. According to experts as well as papers released by reputable organizations like the American Psychiatric Association, drugs don’t get anybody ‘high’, at least not directly. Rather, it is the effect of these substances on the chemical messengers, neurotransmitters, that causes diverse feelings (pleasure, euphoria, relaxation, etc.).

The natural processes of neurotransmitters are enhanced or impeded by almost all drugs, as explained above. Once this imbalance happens, a reaction or action is triggered, thereby causing euphoric effects, among others.

How do Different Drugs Alter the Processes of Neurotransmitters? 

• Dopamine: commonly known for its reward processes, dopamine plays a role in the abuse of almost all substances, though stronger in some, like opiates, meth, and cocaine. Its consistent stimulation significantly increases the risk of powerful drug addictions. 
• Endorphins: These Neurotransmitters are associated with opiate drugs, including pain medications. Endorphins are very potent. Hence, opiates are often considered the strongest type of drug addiction. Oxytocin, morphine, heroin, and fentanyl are some of the substances that endorphins act as chemical messengers. 
• Serotonin: Hallucinogenic drugs are mainly associated with serotonin. It alters sleep and libido in the period of active use. The withdrawal symptoms increase the risk of major alterations to the healthy level of these essential functions. Some examples of these drugs are ecstasy (MDMA), philosopher’s stones, psilocybin mushrooms, and LSD.
• Norepinephrine: Meth and cocaine are examples of substances associated with norepinephrine. Anxiety and altered sensory processing are some of the effects of interfering with normal norepinephrine functioning.
• Glutamate: A large release of glutamate is potentially dangerous and is associated with alcohol, ketamine, and angel dust, among others. Learning and fine and gross motor skills are functions that are at risk of being affected. 
• Anandamide: This chemical messenger is specifically associated with hashish and marijuana. When the normal processes of anandamide are altered, there is an enhanced risk of memory issues. 
• Gamma-Aminobutyric Acid: The processes of GABA are altered by tranquilizers and sedatives, and its effects are potentially dangerous because of its CNS-repressing behavior and sedative action. 

Can Neurotransmitter Disruption Cause Death?

Every drug, prescribed or not, taken alters the processes of the body’s neurotransmitters. This is not always a bad thing. For example, a person with a poor night’s sleep can get a morning boost from caffeine. However, when the substance or/and environment isn’t safe, there’s an increased risk of fatality. Long-term or irreversible damage can equally be done to the brain.

Is Fentanyl (a painkiller) Dangerous?

Though a pain medication, Fentanyl is very strong, about a hundred times stronger than morphine. Therefore, any misuse can be very fatal. When used according to prescription, it is very helpful for people with prolonged and severe pain. 

Can Anyone get Addicted to Drugs?

Yes, anyone can get addicted to drugs. Certain risk factors, like personality traits and addiction history, increase susceptibility, but addiction can happen to anyone. Maintaining awareness of this possibility helps recognize the warning signs early on, such as during painkiller use.

How Does the Body Gets Affected From Addiction?

The body gets affected by addiction by elevating dopamine in the brain’s reward system, triggering neural adaptations that dull pleasure from natural sources, pushing higher and more frequent drug use, causing organ damage, increasing infection risk, and altering mental health.

In addition to the deleterious effects on the individual, addiction also takes a toll on families, communities, and society as a whole. To learn more about the impact of addiction on the body, check out this article.

How is Hyponatremia related to Addiction?

Hyponatremia is related to Addiction. Substances of abuse trigger increased water retention, diluting sodium levels and causing hyponatremia. Addiction-treatment medications also produce hyponatremia as a side effect. Medical monitoring during treatment is essential to prevent and address sodium imbalances.