Heroin sensitivity

February 17, 2005 11:04 PM

With long term heroin use, does one's body "upregulate" or "downregulate" the amount of opioid receptors?

I'm doing a research project and am having a hard time understanding the process of long term drug use. Does the body generate more receptors for opiates or decrease the receptor amount?

posted by icetaco to science & nature (6 comments total)

As far as I understand the process the numbers of opiate receptors actually diminish with the amount of endorphin-like chemicals flooding the brain (this is assuming long term use) and that this diminishment is part of the physiology of addiction; also I believe that they do regenerate, but that this takes time, and is one of the processes of withdrawal.

Again, this is only my understanding, based on nothing scientific but on bits and pieces picked up over time. Can others weigh in?
posted by jokeefe at 12:15 AM on February 18, 2005

The brain downregulates the amount of opioid receptors sensitive to heroin/morphine in respone to chronic use. This is the prevailing model for tolerance in heroin abusers. Check out PubMed (http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed) the google for neuro nerds. The abstracts are just as informative as the whole paper in some cases.

I'll learn how to direct link in a day or two.
posted by Corpus Callosum at 12:17 AM on February 18, 2005

To create a direct link, just click on the "link" button at the bottom of the comment-posting textbox
posted by grouse at 1:29 AM on February 18, 2005

The phenomenon is called tachyphylaxis, tolerance, or down-regulation. It has some surprising and important implications. A decent pharmacology or psychopharmacology textbook, or (my favorite) Carlsson's Physiology of Behavior, will provide a good explanation.
posted by ikkyu2 at 1:36 AM on February 18, 2005

You might search PubMed and Google on the terms "microarray opioid receptors". Microarrays are a tool used to determine up- or down-regulation of genes in various "platforms" (organisms or tissues).
posted by AlexReynolds at 9:02 AM on February 18, 2005

AlexReynolds, if you already know what the opioid receptor genes are (and assuming there's less than a few hundred of them), you don't need a microarray ($$$) to look for variation in mRNA population. I mean, it seems like overkill to me.
posted by rxrfrx at 7:20 AM on February 19, 2005