Serotonin Agonists and Antiserotonin Drugs (5-Hydroxytryptamine, 5-HT)
Serotonin is a neurotransmitter that plays a crucial role in regulating various physiological functions in the body. It is primarily found in the brain, intestines, and blood platelets. Serotonin is synthesized from tryptophan and is involved in the modulation of mood, appetite, sleep, memory, and learning.
Classification
- 5-HT1 Agonists: Sumatriptan, Rizatriptan, Buspirone
- 5-HT2 Agonists: LSD (research purposes)
- 5-HT4 Agonists: Cisapride, Prucalopride
- 5-HT2 Antagonists: Ketanserin, Risperidone, Olanzapine
- 5-HT3 Antagonists: Ondansetron, Granisetron, Palonosetron
- 5-HT4 Antagonists: Mainly for research purposes
Pharmacodynamics
- 5-HT1 Agonists:
- Sumatriptan and rizatriptan act on 5-HT1B and 5-HT1D receptors, causing vasoconstriction of cranial blood vessels and inhibiting the release of pro-inflammatory neuropeptides.
- Used for migraine relief.
- Buspirone acts on 5-HT1A receptors, exerting anxiolytic effects without sedation.
- 5-HT2 Agonists:
- LSD stimulates 5-HT2A and 5-HT2C receptors, leading to altered sensory perception and cognition.
- Used in psychedelic research.
- 5-HT4 Agonists:
- Act on 5-HT4 receptors to enhance gastrointestinal motility.
- Increase acetylcholine release in the enteric nervous system, improving gut motility (used for chronic constipation and GERD).
- 5-HT2 Antagonists:
- Block 5-HT2A and 5-HT2C receptors, helping in schizophrenia and bipolar disorder.
- Reduce dopamine dysregulation, decreasing hallucinations, delusions, and mood disturbances.
- 5-HT3 Antagonists:
- Block 5-HT3 receptors in the central and peripheral nervous systems.
- Prevent activation of the vomiting center in the brain, making them effective in nausea and vomiting prevention (e.g., chemotherapy-induced nausea).