What are the different types of neurotransmitters?

Neurotransmitters can be classified into several categories based on their chemical structure and function. The major types of neurotransmitters include:

1. Amino Acids:
   • These are the most common neurotransmitters in the central nervous system (CNS). They include:
     • Glutamate: The primary excitatory neurotransmitter in the brain, involved in synaptic plasticity and cognitive functions like learning and memory.
     • Gamma-aminobutyric acid (GABA): The main inhibitory neurotransmitter in the brain, which helps to reduce neuronal excitability and prevent overactivity.
     • Glycine: Another inhibitory neurotransmitter, primarily found in the spinal cord and brainstem, that also contributes to inhibitory signaling.
2. Amines:
   • These neurotransmitters are derived from amino acids and include:
     • Acetylcholine (ACh): Involved in muscle activation, attention, and memory; it is the neurotransmitter at neuromuscular junctions and in various brain regions.
     • Dopamine (DA): Plays a key role in reward, motivation, and motor control; dysregulation is associated with disorders like Parkinson’s disease and schizophrenia.
     • Norepinephrine (NE): Involved in arousal, alertness, and the stress response; it acts as both a neurotransmitter and a hormone.
     • Epinephrine (adrenaline): Primarily a hormone, but it can also function as a neurotransmitter in the CNS.
     • Serotonin (5-HT): Regulates mood, appetite, and sleep; it is implicated in mood disorders such as depression.
3. Peptides:
   • These are larger molecules made up of chains of amino acids and include:
     • Substance P: Involved in pain perception and inflammatory responses.
     • Endorphins: Natural pain relievers that also play a role in the reward system and stress response.
     • Neuropeptide Y: Involved in regulating appetite and anxiety.
     • Cholecystokinin (CCK): Plays a role in digestion and satiety.
4. Other Neurotransmitters:
   • There are also other types of neurotransmitters that do not fit neatly into the above categories, such as:
     • Nitric Oxide (NO): A gaseous neurotransmitter that plays a role in vasodilation and neurotransmission; it diffuses across membranes and acts in a retrograde manner.
     • Carbon Monoxide (CO): Another gaseous neurotransmitter that has various roles in the nervous system.