Psycho-Babble Medication | about biological treatments | Framed
This thread | Show all | Post follow-up | Start new thread | List of forums | Search | FAQ

Re:Neuroleptics brain specific antihistaminergic?

Posted by SLS on February 6, 2023, at 19:11:09

In reply to Re:Neuroleptics brain specific antihistaminergic?, posted by undopaminergic on February 6, 2023, at 12:45:07

> > > Next question: Do MAOI increase histamine?
> >
> >
> > Like dopamine (DA), norepinephrine (NE), and serotonin (5-HT), the histamine molecule is a biogenic amine. Monoamine oxides type A (MAO-A) leaves histamine virtually untouched. MAO-B metabolizes (breaks-down) histamine, but to a very small degree. MAO exists *inside* the neuron, but not outside the neuron. Histamine is metabolized *outside* the neuron by an enzyme called diamine oxidase (DAO). Another enzyme located outside the neuron is catechol-O-methyltransferase (COMT). As with the MAO enzyme located inside the neuron, it metabolizes DA, NE, and 5-HT outside the neuron, but to a much smaller degree.

> As the name implies, COMT breaks down catecholamines, but not serotonin.

Good catch. Thanks.

> > I don't know very much about how histamine functions in the body.

> I don't know much about histamine either, but I've read it is the neurotransmitter whose activity is most correlated with wakefulness (and inversely correlated with the lack of wakefulness). This is perhaps not so surprising given the sedative effects of antihistamine drugs.

I'm not sure how many pathways / neurotransmitters are involved with sleep. It's more than one, though. Hypocretin (orexin) is important in maintaining wakefulness. Hypocretin was first labeled as being a neuropeptide. Later, it was found in synaptic vesicles, so it is now often considered to be a neurotransmitter. Another substance that reduces wakefulness and promotes sleep is adenosine. Unlike hypocretin, it is not found in presynaptic vesicles, and is therefore considered a neuropeptide. Adenosine is liberated from the cell membrane along the neuron and into the fluid. There are several types of adenosine receptor. The major role of adenosine is to inhibit wakefulness and promote sleep. Caffeine produces its stimulatory behavioral effects by blocking adenosine receptors, and thus prevents adenosine from performing its role to oppose wakefulness.

Google and PubMed are fun to look through when we are discussing points of interest. I already knew some basics regarding hypocretin, adenosine, and caffeine, but I don't like to leave things that I am uncertain about go unchecked. I start out trying to fact-check what I'm writing, but this usually leads to expanding the scope of the discussion and adding details.

I didn't want to leave you with the impression that I was really that smart. <grin>.

- Scott

P.S. I really should have double-checked COMT. <wink>

Some see things as they are and ask why.
I dream of things that never were and ask why not.

The only thing necessary for the triumph of evil is that good men do nothing.




Post a new follow-up

Your message only Include above post

Notify the administrators

They will then review this post with the posting guidelines in mind.

To contact them about something other than this post, please use this form instead.


Start a new thread

Google www
Search options and examples
[amazon] for

This thread | Show all | Post follow-up | Start new thread | FAQ
Psycho-Babble Medication | Framed

poster:SLS thread:1121718