Neurotransmitters

Definition

Neurotransmitters are chemical messengers that transmit signals across synapses from one neuron to another or to a target cell, playing a crucial role in the nervous system. They influence a variety of physiological functions, including mood, sleep, and muscle contraction, and can have excitatory or inhibitory effects on neuronal activity. These molecules are essential for communication within the brain and throughout the body.

5 Must Know Facts For Your Next Test

1. Neurotransmitters are synthesized and stored in vesicles at the presynaptic neuron before being released into the synaptic cleft.
2. There are many different types of neurotransmitters, including amino acids (like glutamate and GABA), peptides (like substance P), and monoamines (like serotonin and norepinephrine).
3. Once released, neurotransmitters bind to receptors on the postsynaptic neuron, leading to either depolarization or hyperpolarization depending on the type of neurotransmitter and receptor involved.
4. Neurotransmitters can be cleared from the synaptic cleft through reuptake into the presynaptic neuron or degradation by enzymes.
5. The imbalance of neurotransmitters is associated with various neurological and psychiatric disorders, such as depression, anxiety, and schizophrenia.

Review Questions

• How do neurotransmitters influence neuronal communication and what are their potential effects on behavior?
  • Neurotransmitters play a key role in neuronal communication by transmitting signals between neurons at synapses. They can have various effects on behavior depending on whether they are excitatory or inhibitory. For example, excitatory neurotransmitters like glutamate can enhance neuronal firing, potentially leading to increased alertness or anxiety, while inhibitory neurotransmitters like GABA can promote relaxation and calmness. The balance of these neurotransmitters is crucial for maintaining healthy brain function.
• Discuss the differences between excitatory and inhibitory neurotransmitters, providing examples of each.
  • Excitatory neurotransmitters, such as glutamate and acetylcholine, promote the firing of action potentials in neurons, thereby increasing neural activity. In contrast, inhibitory neurotransmitters like GABA and glycine decrease neuronal firing by making it more difficult for an action potential to occur. This balance between excitation and inhibition is essential for normal brain function. An imbalance may lead to neurological issues such as seizures or depression.
• Evaluate the impact of neurotransmitter imbalances on mental health disorders and their treatment options.
  • Neurotransmitter imbalances can significantly affect mental health disorders. For instance, low levels of serotonin are commonly associated with depression, while excessive dopamine activity is linked to schizophrenia. Understanding these imbalances has led to targeted treatment options such as selective serotonin reuptake inhibitors (SSRIs) for depression, which aim to increase serotonin levels in the brain. Treatments may also include antipsychotics that target dopamine receptors. This evaluation highlights the importance of neurotransmitter systems in developing effective therapeutic strategies for various mental health conditions.

Related terms

Synapse: The junction between two neurons where neurotransmitters are released to facilitate communication.

Receptors:

Proteins on the surface of neurons that bind to neurotransmitters, triggering a response in the receiving cell.

Dopamine: A specific type of neurotransmitter involved in reward, motivation, and motor control, often linked to feelings of pleasure.