synaptic signaling via neuropeptide

Definition

Target type: biologicalprocess

Cell-cell signaling to or from a synapse, mediated by a peptide. [GOC:dos]

Synaptic signaling via neuropeptides is a complex and multifaceted process that involves the synthesis, release, and reception of neuropeptides at synapses. Here's a detailed breakdown:

1. **Neuropeptide Synthesis:** Neuropeptides are small protein-like molecules synthesized in the cell bodies of neurons. Their synthesis often involves a precursor protein that is cleaved into smaller active peptides.
2. **Packaging and Transport:** Once synthesized, neuropeptides are packaged into secretory vesicles within the neuron. These vesicles are transported along the axon to the presynaptic terminal, where they are stored.
3. **Signal Arrival and Depolarization:** An action potential arriving at the presynaptic terminal triggers a series of events leading to neuropeptide release. The action potential causes an influx of calcium ions (Ca2+) into the terminal.
4. **Vesicle Fusion and Release:** The influx of Ca2+ triggers the fusion of the neuropeptide-containing vesicles with the presynaptic membrane. This fusion event releases the neuropeptides into the synaptic cleft, the small gap between the presynaptic and postsynaptic neurons.
5. **Neuropeptide Diffusion:** Once released, neuropeptides diffuse across the synaptic cleft and bind to specific receptors on the postsynaptic membrane.
6. **Postsynaptic Receptor Binding:** The binding of neuropeptides to their receptors activates signaling pathways within the postsynaptic neuron. These pathways can involve a variety of intracellular signaling molecules, including G-proteins, second messengers, and kinases.
7. **Signal Transduction and Cellular Response:** The activated signaling pathways lead to changes in the postsynaptic neuron's activity, influencing its excitability, neurotransmitter release, gene expression, or other cellular processes.
8. **Termination of Signaling:** Neuropeptide signaling is terminated through several mechanisms:
- **Reuptake:** Some neuropeptides are taken back up into the presynaptic neuron or surrounding glial cells.
- **Enzymatic Degradation:** Neuropeptides can be broken down by enzymes in the synaptic cleft.
- **Diffusion:** Neuropeptides can simply diffuse away from the synapse.

Synaptic signaling via neuropeptides plays a crucial role in a wide range of physiological processes, including:
- **Pain Perception:** Neuropeptides like substance P and endorphins are involved in pain signaling.
- **Stress Response:** Neuropeptides like corticotropin-releasing hormone (CRH) and adrenocorticotropic hormone (ACTH) play a role in the stress response.
- **Mood Regulation:** Neuropeptides like endorphins and oxytocin are associated with mood regulation.
- **Appetite and Satiety:** Neuropeptides like neuropeptide Y (NPY) and leptin influence appetite and satiety.
- **Social Behavior:** Neuropeptides like oxytocin and vasopressin are involved in social bonding and behavior.
- **Learning and Memory:** Neuropeptides like vasopressin and oxytocin can influence learning and memory processes.'
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Proteins (1)

Compounds (8)