opiate + opiate agonist?

[xEx]

does opiate agonist mean it works against opiate receptors? thats a blind guess, so any help would be appreciated. my doc put me on lortab + ultram. thanks
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like a fat kid in dodgeball, I'M OUT

 

[Deus121]

It means it binds to opiate receptors which causes release of endorphins, and encephalins, the bodies natural opiates. BOTH those drugs are opiate agonists.
[This message has been edited by Deus121 (edited 17 November 2001).]

 

[zorn]

An opioid agonist is something that binds to the opioid receptor triggers it (kinda like a key opening a lock), such as morphine, heroin, etc. An opioid antagonist is something that prevents the receptor from being triggered at all (kinda like pouring glue in the lock), such naloxone which is used to treat opioid ODs. There are also mixed agonist/antagonists, which trigger the receptors but only to a certain level -- kind of like opening the lock halfways, but preventing it from being opened further.
-Zorn

 

[zorn]

Deus--
Not quite. Endorphins, enkephalins, and dynorphins are the body's natural opioid agonists, basically natural morphine. They are what binds to opioid receptors in your body, not what gets released.

 

[Deus121]

Zorn - Oh, sorry, I was going by what I read in the Medical Journal. If I'm wrong please show me where you get your information from.

 

[zorn]

Zeus--
Lessee, I don't really have references... I mean these are pretty basic definitions. I guess the best place would be an introductory biology text covering molecular biology. You can lookup the definitions at the online medical dictionary http://www.graylab.ac.uk/omd/ though the definitions themselves may not make any sense if you don't already know med/bio terminology.
-Zorn

 

[zorn]

Oh, and you're right, both lortabs (hydrocodone+acetaminophen) and ultram (tramadol) are opioid agonists. The acetaminophen (tylenol) in lortabs is what's known as a NSAID, and blocks pain in a non-opioid related way. Tramadol also induces serotonin release and blocks norepinephrine uptake, which seems to help with pain relief.
-Zorn

 

[PhreeX]

Sadly I was beat to the answer, but I REALLY like this definition -

"An opioid agonist is something that binds to the opioid receptor triggers it (kinda like a key opening a lock), such as morphine, heroin, etc. An opioid antagonist is something that prevents the receptor from being triggered at all (kinda like pouring glue in the lock), such naloxone which is used to treat opioid ODs. There are also mixed agonist/antagonists, which trigger the receptors but only to a certain level -- kind of like opening the lock halfways, but preventing it from being opened further."

VERY GOOD ANALOGY! Even a, well, candy raver could follow that explaination..
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"I am not one of those weak-spirited, sappy Americans who want to be liked by all the people around them. I don't care if people hate my guts; I assume most of them do. The important question is: 'What are they in a position to do about it?'" (William S. Burroughs)

 

[min]

Zorn--It's about time we saw someone clear up the confusion between agonist and antagonists. However, I was under the impression that antagonists also bond to opiate/endorphin receptors, that they in fact bond more tightly to them than agonists do, thereby either reversing or inhibiting their action. Am I correct?

 

[zorn]

I'm no biochemist, but yeah, that's the basic idea, hence the glue-in-the-lock analogy. There are a couple different classifications of antagonists.
Irreversible antagonists typically bond covalently to a receptor and stick to it for a long time. Reversible antagonists bind more weakly, and so the ones blocking the receptor are in equilibrium with other ligands around it. Another distinction is competitive vs. non-competitive; competitive antagonists actually bind to the receptor where an agonist would, but don't trigger it, eg glue in the lock. Non-competitive antagonists bind to a different site on the receptor, and "allosterically" alter the receptor in some way to attenuate its function... guess the analogy would be taping the door shut.
-Zorn