Neurotransmitter
This article explains the types of neurotransmitters and the effects of several important neurotransmitters on the body.
Understanding neurotransmitters will help players in the following chapters:
Related knowledge about neurotransmitters includes:
Types
Several common neurotransmitters are as follows:
| Name | Type | Function |
|---|---|---|
| Dopamine | Catecholamines | Related to reward, motivation, pleasure, and motor control |
| Epinephrine | Catecholamines | Involved in stress response Also a hormone, see Hormones: Epinephrine |
| Endorphins | Peptides | Relieve pain, create feelings of pleasure |
| Serotonin | Monoamines | Affect mood, sleep, appetite, and cognition |
| Glutamate | Amino Acids | The main excitatory neurotransmitter, involved in learning and memory |
| Gamma-Aminobutyric Acid | Amino Acids | The primary inhibitory neurotransmitter, regulates neural activity and prevents overexcitation. |
| Acetylcholine | Others | Involves muscle control, memory, and attention |
| Nitric Oxide | Gases | As a gas neurotransmitter, regulates vasodilation and neural signaling |
| Substance P | Peptides | Participates in the regulation of sensation, movement, and emotion |
| Oxytocin | Peptides | Regulates emotions, social behavior, and reproductive functions Also a hormone, see Hormones: Oxytocin |
Dopamine
Dopamine (DA) has various important functions in the brain, including motor control, motivation, arousal, enhancement, reward system, breastfeeding, sexual climax, and nausea, primarily related to the modulation of motor behavior and the elicitation of pleasure related to motivation and emotions.
There are very few neurons in the human brain that can produce dopamine, numbering only around 400,000, and their cell bodies are only found in a few areas of the brain. However, their axons can extend throughout other regions of the brain and have a strong influence on their target areas.
Dopamine acts as a reward signal throughout the brain (🔗Reward System). It is generally believed that dopamine is a substance that produces pleasure. While dopamine indeed brings pleasure, pleasure is not solely produced by dopamine; in fact, dopamine is a substance that records the significance of incentives. In other words, dopamine indicates desire or aversion towards a certain outcome, then drives individuals to bring it about or avoid it.
Parkinson's disease[1] is associated with dopamine deficiency; schizophrenia is linked to higher levels of dopamine; Restless Legs Syndrome[2] and Attention Deficit Hyperactivity Disorder[3] are related to reduced dopamine activity.
Dopamine is also connected to addiction and drug use, as most recreational drugs result in surges of dopamine (especially opioids and methamphetamine) in the brain, thus producing pleasurable feelings, which explains the constant craving of addicts for drugs.
Endorphins
Endorphins are typically produced in the brain and adrenal medulla during physical exercise or sexual climax, inhibiting pain, muscle spasms, alleviating stress, and enhancing feelings of happiness.
Intense aerobic exercise can trigger the production of endorphins, such as running. The same phenomenon may also play a role in exercise addiction. Regular intense exercise may lead to a downregulation of endorphin production during rest periods in the brain to maintain internal balance, causing an individual to exercise more intensely to achieve the same feelings.
Serotonin
Serotonin (5-HT), also known as 5-hydroxytryptamine, contributes to feelings of happiness and joy. Approximately 90% is synthesized in the gut, with the remainder synthesized in the central nervous system. It regulates appetite, sleep, memory and learning, body temperature, mood, behavior, muscle contraction, cardiovascular system, endocrine system, and more.
Many health issues are related to low levels of serotonin in the brain. There are numerous reasons for the decrease of serotonin, including stress, lack of sleep, malnutrition, and lack of exercise. When levels drop below the required amount, people may experience difficulties in concentrating and other issues that indirectly affect personal planning and organizational abilities. This condition is often accompanied by stress and feelings of boredom, and if serotonin levels drop further, patients may exhibit unnecessary aggressive behaviors and mood swings, potentially leading to depression.
Glutamate
Glutamate is the most abundant excitatory neurotransmitter in the central nervous system, used in every major excitatory function of the brain, making up over 90% of synaptic connections in the human brain. Glutamate participates in cognitive functions such as learning and memory in the brain and plays an important role in regulating growth cones and synaptogenesis during brain development.
Excessive glutamate can lead to excitotoxicity, and it is associated with diseases such as stroke, autism, certain forms of intellectual disabilities, and amyotrophic lateral sclerosis[4] and Alzheimer's disease[5].
Gamma-Aminobutyric Acid
Gamma-Aminobutyric Acid (GABA) is the main inhibitory neurotransmitter in the mature central nervous system, primarily acting to decrease the excitability of neurons across the entire nervous system. However, in the developing nervous system, it substitutes for glutamate and acts as an excitatory neurotransmitter. Gamma-Aminobutyric Acid is the basis for many sedative medications.
Acetylcholine
Acetylcholine (ACh) is the neurotransmitter that controls muscle contraction at the neuromuscular junction and is also an internal neurotransmitter of the sympathetic and parasympathetic nervous systems. It is one of the very ancient compounds in the evolution of life.
Acetylcholine plays an essential role in arousal, rapid eye movement sleep, attention, learning, memory, and motivation. Damage to its synthesis system is associated with memory deficits related to Alzheimer's disease.
In cardiac tissue, acetylcholine has an inhibitory effect on neurotransmission, thereby reducing heart rate. Excessive inhalation of acetylcholine may cause the heart to react excessively, leading to tight contractions that cannot relax, resulting in cardiac failure and death.
Many toxins and venoms produced by various plants, animals, and bacteria, as well as chemical nerve agents like sarin, attack the nervous system by interfering with the degradation of acetylcholine, causing muscles to become inactive or overly active, resulting in injury.
Decomposition
Once each neurotransmitter reaches the postsynaptic cell, it must be broken down to prevent further excitatory or inhibitory signal transduction (terminate synaptic transmission).
The termination of the neurotransmitter signal can rely on the hydrolytic enzymes corresponding to the synaptic cleft or postsynaptic membrane to degrade, or by specific presynaptic membrane neurotransmitter transporters reabsorbing them. For example, acetylcholine is degraded by acetylcholinesterase into acetate and choline. Other neurotransmitters, such as dopamine, can diffuse away from target cells and be excreted by other parts of the body, such as the kidneys, or be broken down by the liver.
Translation Note
The original text is in Chinese, and the English translation was generated automatically by ChatGPT. There may be inaccuracies or errors in the translation; please refer to the original text for accuracy.
Parkinson's disease, a chronic neurodegenerative disease that affects the central nervous system, primarily the motor nervous system, symptoms typically progress slowly over time, with the most obvious early symptoms being tremors, rigidity, reduced motor function, and gait abnormalities. Cognitive and behavioral issues may also occur; dementia is quite common in severely affected patients, with over a third of cases also experiencing major depressive disorders and anxiety. ↩︎
Restless Legs Syndrome, a disorder characterized by the intense urge to move the legs. Patients often experience an unpleasant sensation in the legs that improves with movement; discomfort can feel like pain, tingling, or crawling sensations, and occasionally the arms may also be affected. Restless Legs Syndrome usually occurs at rest, making it difficult for patients to fall asleep. Due to poor sleep, patients may feel excessively sleepy, have difficulty concentrating, be irritable, and experience low mood during the day. ↩︎
Attention Deficit Hyperactivity Disorder is a mental disorder characterized by difficulty focusing, excessive activity, and acting without considering consequences, among other traits. Additionally, individuals with attention deficits may exhibit age-inappropriate behavior and difficulties in emotional regulation or executive functioning. ↩︎
Amyotrophic Lateral Sclerosis (ALS), commonly known as Lou Gehrig's disease, is a motor neuron disease characterized by simultaneous involvement of the cortical motor neurons, brainstem motor neuron nuclei, and anterior horn cells of the spinal cord; it is a progressive and fatal neurodegenerative disease. It is one of the five most common types of motor neuron diseases. ↩︎
Alzheimer's disease, commonly referred to as senile dementia, is a neurodegenerative disease that progresses slowly, worsening over time. It accounts for 60-70% of all dementia cases. The most common early symptom is the loss of short-term memory (difficulty remembering recent events); as the disease progresses, symptoms may gradually emerge, including language difficulties, orientation problems, and self-care issues (such as getting lost easily), mood instability, loss of motivation, inability to care for oneself, and many behavioral problems. As conditions worsen, patients often become disconnected from family or society and gradually lose bodily functions, ultimately leading to death. ↩︎