cmgannon26 wrote:
I agree with the guys that are saying unless you are already prescribed promethazine as an anti-emetic, you probably won't want to use it in your FAK. It's got some nasty side effects not due to its anti-histamine action, but its anticholinergic effects. (It's action on acetylcholine receptors is what makes it sedating and what makes people go "bat shit crazy", not its anti-histamine action. Histamine is not a neurotransmitter. ACh is. Also, delerium due to acute anticholinergic syndrome really only occurs when too much is administered.)
I am pretty sure there are histamine receptors in the cortex. Doesn't the medial forebrain bundle have histamine neurons in it? I know that it carries norepinephrine tracts, and the whole "hedonic highway" thing with dopamine, but I thought there was some histamine in there also. Going to try and find a literature reference.
As far as the anti-cholinergic effects, of that I was not aware. Thanks for the info there. Maybe promethazine does not block the H1/H2/H3 (whatever they are) receptors in the cortex?
Ok, this is what I found, for your discussion:
Quote:
Histamine-releasing neurons are located exclusively in the TM of the hypothalamus, from where they project to practically all brain regions, with ventral areas (hypothalamus, basal forebrain, amygdala) receiving a particularly strong innervation.
Quote:
The central histamine system is involved in many central nervous system functions: arousal; anxiety; activation of the sympathetic nervous system; the stress-related release of hormones from the pituitary and of central aminergic neurotransmitters; antinociception; water retention and suppression of eating. A role for the neuronal histamine system as a danger response system is proposed.
ref: Brown RE, Stevens DR, Haas HL. The physiology of brain histamine. Prog Neurobiol. 2001 Apr;63(6):637-72.
http://www.ncbi.nlm.nih.gov/pubmed/11164999I will be honest, I only read the abstract. I could link the full article on Elsevier if anyone cared, but I didn't think they would. There are a few more articles, but I did not have full article access in case somebody called BS...
One more, same info w/ full text, just the link to abstract:
http://www.ncbi.nlm.nih.gov/pubmed/1862 ... dinalpos=6