What Do The Following Terms Mean in Psychiatry: Inhibitor, Antagonist, Agonist? - Bipolar Disorder Message Board

Baby Bunny · 06-08-2007, 06:50 AM

Hi all. It's me once again. LOL

I am just wondering if someone would please be so kind as to explain to me in layman's (sp?) terms what the words in the subject title actually mean in regard to psychitry. Also what about CYP-2D6 and CYP-3A4?

My new medication, Invega (Palperidone) says the following and I'd just like to know a bit more about what I'm reading and taking:

Properties:
*Benzisoxazole
DA2 antagonist
5-HT2A antagonist
NE alpha-1 antagonist
NE alpha-2 antagonist
H1 antagonist

Half-Life & Metabolism:
23 Hours
CYP-2D6
CYP-3A4

I believe that DA2 is a kind of Dopamine, 5-HT2A is some type of Serotonin, NE Alpha 1 & 2 are some kinds of Norepinephrine and H1 is a type of Histamine.

But in all honesty I really don't know much about this stuff. Can ya tell? LOL So if anyone would be so kind as to please enlighten me I'd be most thankful. I really would like to know more about what I'm putting into my body and what it's doing in there.

Thanks again.

Hugs,
BB

NutshellNutter · 06-08-2007, 09:02 AM

Hi Babybunny,
CYP's are cytochrome P450's (enzymes that are present in the liver and are utilised in various biochemical cascades) - there are various sorts such as 2D6, 3A4 etc...

DA2 isn't a type of dopamine - it is a specific nomeclature for a specific type of dopamine 'receptor' in the brain. The same for 5HT2A, 5HT1A - these are both types of serotonin receptors found in the brain.

Molecules (drugs or naturally occuring molecules such as dopamine / serotonin) that bind to these receptors (like a key on a lock) may be termed either antagonists or agonists. These two words are the oppositie of each other - antagonists work against the receptor to which they bind (ie. decrease the effect of the receptor binding), agonists work to promote the effect of receptor binding. Molecules (biological / drugs) may be either antagonistic OR agonistic for the receptor to which they are targeted.

You will commonly hear of 'reuptake inhibitor' with relation to SSRI anti-deps. These work by binding to the serotonin receptors and prevent the serotonin being taken back up by the terminal which released it - therefore the serotonin remains in the synapse for longer, and the 'feel good' signal lasts forl onger than normal.

Hope that helps,

Nut.