Neurotransmitter

Definition

A neurotransmitter is a chemical messenger that transmits signals across synapses from one neuron to another, influencing the activity of the receiving neuron. These chemicals play a critical role in the functioning of the nervous system, facilitating communication between neurons and modulating various processes such as mood, sleep, and cognition. By binding to specific receptors on the post-synaptic neuron, neurotransmitters can either excite or inhibit neuronal activity, making them essential for maintaining homeostasis in neural networks.

5 Must Know Facts For Your Next Test

1. There are over 100 different types of neurotransmitters in the human brain, each with specific functions and roles.
2. Common neurotransmitters include dopamine, serotonin, and acetylcholine, which are involved in regulating mood, memory, and muscle control.
3. Neurotransmitter release is triggered by an influx of calcium ions into the presynaptic neuron, which occurs when an action potential reaches the terminal.
4. After binding to receptors on the post-synaptic neuron, neurotransmitters can be removed from the synapse through reuptake or enzymatic degradation to prevent continuous stimulation.
5. Imbalances in neurotransmitter levels can lead to various neurological and psychiatric disorders, highlighting their importance in brain function.

Review Questions

• How do neurotransmitters influence neuronal communication and what processes are they involved in?
  • Neurotransmitters are essential for neuronal communication as they transmit signals across synapses. When released from a presynaptic neuron, they bind to receptors on a post-synaptic neuron, causing changes in its membrane potential. This process can either excite or inhibit the receiving neuron, affecting various processes such as mood regulation, sleep patterns, and cognitive functions. Therefore, neurotransmitters play a crucial role in shaping how neurons interact and function within neural networks.
• Compare and contrast the roles of excitatory and inhibitory neurotransmitters in regulating neuronal activity.
  • Excitatory neurotransmitters, like glutamate, increase the likelihood that a neuron will fire an action potential by depolarizing the post-synaptic membrane. In contrast, inhibitory neurotransmitters, such as gamma-aminobutyric acid (GABA), decrease this likelihood by hyperpolarizing the membrane. This balance between excitatory and inhibitory signals is critical for maintaining proper neural function and preventing conditions such as seizures or anxiety disorders. Both types of neurotransmitters work together to regulate overall brain activity.
• Evaluate the impact of neurotransmitter imbalances on neurological disorders and discuss potential therapeutic approaches.
  • Neurotransmitter imbalances are linked to numerous neurological and psychiatric disorders such as depression, anxiety, schizophrenia, and Parkinson's disease. For instance, reduced serotonin levels are associated with depression, while dopamine dysregulation can contribute to Parkinson's symptoms. Therapeutic approaches often involve pharmacological interventions aimed at correcting these imbalances through reuptake inhibitors or receptor modulators. By targeting specific neurotransmitter systems, these treatments aim to restore balance and improve symptoms associated with these disorders.

Related terms

Synapse:

The junction between two neurons where neurotransmitters are released and received, enabling communication between the cells.

Receptors: Proteins located on the surface of neurons that bind to neurotransmitters, triggering responses in the receiving cell.

Action Potential:

A rapid change in membrane potential that propagates along a neuron, leading to the release of neurotransmitters at the synapse.