serotonin (thing)

Many different serotonin receptors have been discovered; they have been divided into subtypes:

• 5-HT_1A: activation of these receptors inhibits firing of serotonin neurons and lowers the release of serotonin in the prefontal cortex; this receptor controls mood and is implicated in depression.
• 5-HT_1B: controls the release of other neurotransmitters, and connected to aggression, implicated in learning and memory dysfunctions.
• 5-HT_1D: the drug Sumatripan (Imitrex) is a 5-HT1D agonist used in treating migraine and cluster headaches.
• 5-HT_1E
• 5-HT_1F: possibly linked to migraine headaches.


• 5-HT_2A: increased density of this subtype can indicate an increased risk of suicide.
• 5-HT_2B: 2B & 2C subtypes have an inhibitory effect on the mesolimbic and nigrostriatal dopamine pathways; stimulation of the 2B receptor reduces anxiety and tension, and this receptor is found throughout the body.
• 5-HT_2C: see above; may be responsible for regulation of cerebral spinal fluid, as well as sleep.


• 5-HT_3A: 3A & 3B subtypes are linked to vomiting; ondansetron, granisetron, dolasetron, palonesetron, and alosetron are all antiemetic 5-HT3 antagonists.
• 5-HT_3B: see above.


• 5-HT_4A: 4A & 4B are connected to dopamine function, and may also be responsible for inducing tachycardia.
• 5-HT_4B: see above.


• 5-HT_5A
• 5-HT_5B


• 5-HT₆: involved in cognitive functions such as learning and memory.


• 5-HT_7A
• 5-HT_7B
• 5-HT_7C
• 5-HT_7D

Serotonin's chemical structure:

                H
                 \
           H  H   N
            \  \ / \
 H   H       C--C   H
  \   \     / \  \
   O   C   C   H  H
    \ / \\/ \\
     C   C   C
    ||   |   /\
     C   C--N  H
    / \ //   \
   H   C      H
        \
         H