Posted by madeline on December 6, 2006, at 7:30:28
In reply to Re: It's All Japanese to Me! » madeline, posted by MM on December 6, 2006, at 1:40:31
"So, does an antagonist cause the body to make more of whatever it's blocking? I think I'm confusing re-uptake inhibitors with antagonists or something..."
Okay, the question you are asking is a very complicated one. Frankly, antagonists rarely just sit on the receptor and block its interaction with agonist, but let's talk about reuptake inhibitors.
Specifically, let's look at the selective serotonin reuptake inhibitors (SSRIs).
Serotonin is a neurotransmitter in the brain, that means it is a hormone that lets brain cells talk and listen to each other.
When one brain cell (the talker) has something to say, it releases serotonin and another brain cell (the listener) interacts with serotonin and does what the talking cell says to do. The listening cell binds serotonin via serotonin receptors on its surface.
When the listening cell has processed the message they let the serotonin go from the receptors and - here's the kicker - the talking cell picks the serotonin back up.
Picking the serotonin back up is called "serotonin reuptake".
Alright, one of the fundamental theories of depression is that the depressed brain is deficient in serotonin so the listening cell doesn't get a clear message from the talking cell.
So SSRI's block the reuptake of serotonin by the talking cell thus keeping serotonin around longer and at a higher concentration than without the drug.
The theory is that this makes the signal "clearer" and allows the listening cell to more effectively process what it is supposed to do.
What makes SSRI's different from the classical antagonist is that they don't bind to the serotonin receptor on the listening cell and BLOCK the action of serotonin there.
They bind to the reuptake receptors on the talking cell and BLOCK the reuptake of serotonin.
SSRI's are antagonists, but they don't block at the agonist receptor for serotonin.
The principle is the same for a lot of other reuptake inhibitors for other neurotransmitters.
Hope this clears this up.
Maddie
poster:madeline
thread:709764
URL: http://www.dr-bob.org/babble/alter/20061203/msgs/710802.html