Chapter 12 - Section 12.5 - Study Guide - Assess Your Learning Outcomes - Page 471: 3

Neurotransmitters are chemical messengers that transmit signals from one neuron to another across synapses. They can be categorized into several classes based on their chemical structure and function. Here are some of the main categories of neurotransmitters and common examples of each: 1. **Amino Acid Neurotransmitters:** - These neurotransmitters are derived from amino acids and are among the most common in the nervous system. - **Glutamate:** Excitatory neurotransmitter. It is involved in learning, memory, and the majority of excitatory synaptic transmission in the brain. - **GABA (Gamma-Aminobutyric Acid):** Inhibitory neurotransmitter. It plays a key role in reducing neuronal excitability and is important for maintaining the balance between excitation and inhibition in the brain. 2. **Biogenic Amines:** - Biogenic amines are derived from amino acids and play various roles in mood regulation, sleep, and arousal. - **Dopamine:** Involved in reward, motivation, motor control, and mood regulation. Dysregulation of dopamine is associated with conditions like Parkinson's disease and schizophrenia. - **Serotonin:** Regulates mood, sleep, appetite, and anxiety. Imbalances in serotonin are linked to depression and anxiety disorders. - **Norepinephrine (Noradrenaline):** Involved in the "fight or flight" response, regulating alertness, and mood. Dysregulation can contribute to conditions like depression and anxiety. 3. **Acetylcholine (ACh):** - Acetylcholine is a neurotransmitter that plays a crucial role in muscle contraction, memory, and cognitive functions. - It is released at neuromuscular junctions and is also found in the central nervous system, where it is involved in various cognitive processes. 4. **Neuropeptides:** - Neuropeptides are larger molecules than classical neurotransmitters and often act as neuromodulators, influencing the activity of neurons rather than directly transmitting signals. - **Substance P:** Involved in pain perception and the transmission of pain signals. - **Oxytocin:** Plays a role in social bonding, trust, and maternal behaviors. 5. **Purines:** - **Adenosine:** Acts as an inhibitory neurotransmitter and plays a role in sleep regulation and the relaxation of blood vessels. 6. **Gasotransmitters:** - Gasotransmitters are small, gaseous molecules that function as neurotransmitters. - **Nitric Oxide (NO):** Acts as a signaling molecule in the nervous system, regulating blood flow and synaptic plasticity. 7. **Endocannabinoids:** - **Anandamide and 2-Arachidonoylglycerol (2-AG):** These lipid-based neurotransmitters play roles in pain modulation, appetite, and mood regulation. They are involved in the endocannabinoid system. 8. **Trace Amines:** - Trace amines are a class of neurotransmitters that include compounds like tyramine and phenylethylamine. They have various roles, including modulation of mood and arousal. These categories and neurotransmitter examples provide an overview of the diverse chemical messengers involved in neural communication. Each neurotransmitter has specific functions and receptor systems in the brain and nervous system, and imbalances or dysregulation of these neurotransmitters can lead to various neurological and psychiatric disorders.

Neurotransmitters are chemical messengers that transmit signals from one neuron to another across synapses. They can be categorized into several classes based on their chemical structure and function. Here are some of the main categories of neurotransmitters and common examples of each: 1. **Amino Acid Neurotransmitters:** - These neurotransmitters are derived from amino acids and are among the most common in the nervous system. - **Glutamate:** Excitatory neurotransmitter. It is involved in learning, memory, and the majority of excitatory synaptic transmission in the brain. - **GABA (Gamma-Aminobutyric Acid):** Inhibitory neurotransmitter. It plays a key role in reducing neuronal excitability and is important for maintaining the balance between excitation and inhibition in the brain. 2. **Biogenic Amines:** - Biogenic amines are derived from amino acids and play various roles in mood regulation, sleep, and arousal. - **Dopamine:** Involved in reward, motivation, motor control, and mood regulation. Dysregulation of dopamine is associated with conditions like Parkinson's disease and schizophrenia. - **Serotonin:** Regulates mood, sleep, appetite, and anxiety. Imbalances in serotonin are linked to depression and anxiety disorders. - **Norepinephrine (Noradrenaline):** Involved in the "fight or flight" response, regulating alertness, and mood. Dysregulation can contribute to conditions like depression and anxiety. 3. **Acetylcholine (ACh):** - Acetylcholine is a neurotransmitter that plays a crucial role in muscle contraction, memory, and cognitive functions. - It is released at neuromuscular junctions and is also found in the central nervous system, where it is involved in various cognitive processes. 4. **Neuropeptides:** - Neuropeptides are larger molecules than classical neurotransmitters and often act as neuromodulators, influencing the activity of neurons rather than directly transmitting signals. - **Substance P:** Involved in pain perception and the transmission of pain signals. - **Oxytocin:** Plays a role in social bonding, trust, and maternal behaviors. 5. **Purines:** - **Adenosine:** Acts as an inhibitory neurotransmitter and plays a role in sleep regulation and the relaxation of blood vessels. 6. **Gasotransmitters:** - Gasotransmitters are small, gaseous molecules that function as neurotransmitters. - **Nitric Oxide (NO):** Acts as a signaling molecule in the nervous system, regulating blood flow and synaptic plasticity. 7. **Endocannabinoids:** - **Anandamide and 2-Arachidonoylglycerol (2-AG):** These lipid-based neurotransmitters play roles in pain modulation, appetite, and mood regulation. They are involved in the endocannabinoid system. 8. **Trace Amines:** - Trace amines are a class of neurotransmitters that include compounds like tyramine and phenylethylamine. They have various roles, including modulation of mood and arousal. These categories and neurotransmitter examples provide an overview of the diverse chemical messengers involved in neural communication. Each neurotransmitter has specific functions and receptor systems in the brain and nervous system, and imbalances or dysregulation of these neurotransmitters can lead to various neurological and psychiatric disorders.