Drugs targeting histamine receptors are also often used to treat insomnia. Antihistamines have been used as sleep aids for decades, even though mechanisms of action have yet to be fully explained. In mammals, histamine is made by the TMN and signals through four histamine receptors (H1–H4). Histamine receptors are found in various areas of the brain including the cerebral cortex, the LC, and the basal forebrain. H1 knockout mice were found to have increased non-REM sleep. The link between histamine and wakefulness has been shown in model organisms. For example, injection of histamine into the basal forebrain which is a wake-promoting area was found to increase wakefulness in rats while use of H1 receptor antagonists reduced this effect (6). Histamine’s regulation of wakefulness has also been shown in zebrafish. Overall, antihistamines likely at as H1 receptor antagonists and promote sleep by directly blocking wakefulness from histamine signaling (6).
This is a very interesting section to read on! From investigation of melatonin, I learn that tryptophan (an amino acid) is a precursor of melatonin. From here, I learn that histamine also regulate sleep rhythm but it has histidine as precursor. This is so cool! Considering how A.A also play a role in gluconeogenesis. For suggestion, I would suggest combining two or three of the section of answer sub sections together. To me, I was not able to see an “unified” answer to the question but listing of reason to the question.
Because there are so many drug treatments for insomnia that each have unique mechanisms and act on different receptors in the brain, we wanted to keep each major drug group as a separate section.
are these traditional anti-histamines or which compounds were used? also this diagram is a bit vague in that mouse models will use a variety of injection sites to get drugs into the brain including injections into veins in the face and brain which can skew the picture you are painting.
correction: this is synthesis pathway so i was wrong. but same question regarding which histamine drugs
I have only briefly read about the effects of histamine on wakefulness, so this page was really cool. I know antihistamines control inflammation, but I wonder why they decrease wakefulness. It reminds me of how Benadryl makes people sleepy, even though its main function is for allergic reactions. Maybe falling asleep during an allergic reaction or the beginning stages of wound healing is a bad idea from the evolution perspective.
The main two things I feel this page is missing are: examples of antihistamines (easy to add) and a better transition from the research to your conclusion. I think a basic summary of the research before the conclusion would be sufficient.