Neurotransmitters

Definition

Neurotransmitters are chemical messengers that transmit signals across synapses from one neuron to another in the nervous system. They play a vital role in communication within the brain and throughout the body, influencing various physiological processes, emotions, and behaviors. By binding to specific receptors on target cells, neurotransmitters can either excite or inhibit those cells, facilitating complex signaling pathways.

5 Must Know Facts For Your Next Test

1. Neurotransmitters can be classified into different categories, such as excitatory (e.g., glutamate) and inhibitory (e.g., gamma-aminobutyric acid or GABA), based on their effects on target cells.
2. Common neurotransmitters include dopamine, serotonin, norepinephrine, and acetylcholine, each having distinct roles in regulating mood, arousal, and various bodily functions.
3. The synthesis and release of neurotransmitters are tightly regulated processes involving several enzymes and signaling mechanisms to ensure proper neuronal communication.
4. After neurotransmitters bind to their receptors, they can be recycled through reuptake into the presynaptic neuron or broken down by enzymes in the synaptic cleft.
5. Disruptions in neurotransmitter signaling are linked to various neurological and psychiatric disorders, including depression, anxiety, schizophrenia, and Parkinson's disease.

Review Questions

• How do neurotransmitters influence communication between neurons?
  • Neurotransmitters influence communication between neurons by being released from presynaptic neurons into the synaptic cleft and binding to receptors on postsynaptic neurons. This binding can lead to either excitation or inhibition of the postsynaptic neuron, depending on the type of neurotransmitter and its receptor. This process is essential for transmitting signals throughout the nervous system and ensuring coordinated responses to stimuli.
• Discuss the role of vesicles in the release of neurotransmitters at synapses.
  • Vesicles play a crucial role in the release of neurotransmitters at synapses by storing them until an action potential triggers their release. When an action potential reaches the presynaptic terminal, calcium ions enter the neuron and stimulate vesicles to fuse with the plasma membrane. This fusion releases neurotransmitters into the synaptic cleft, where they can then bind to receptors on adjacent neurons and propagate the signal.
• Evaluate the implications of disrupted neurotransmitter signaling in neurological disorders.
  • Disrupted neurotransmitter signaling can have severe implications in neurological disorders, as it often leads to imbalances that affect mood regulation, cognition, and motor functions. For example, reduced dopamine levels are associated with Parkinson's disease, leading to motor deficits, while serotonin imbalance is linked to depression. Understanding these disruptions helps in developing targeted therapies that can restore proper signaling pathways and improve patient outcomes.

Related terms

Synapse: The junction between two neurons where neurotransmitters are released and received, allowing for communication between nerve cells.

Receptors:

Proteins located on the surface of target cells that bind to neurotransmitters and initiate cellular responses.

Vesicles: Small membrane-bound sacs within neurons that store neurotransmitters and release them into the synaptic cleft during neurotransmission.