How does buprenorphine block opiates?

A review of the specific actions buprenorphine causes in the central nervous system, by Dr. Jeffrey Junig.

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How buprenorphine blocks opiates

In biochemistry and pharmacology, a ligand is a substance (usually a small molecule), that forms a complex with a bio molecule to serve a biological purpose. Ligands bind to central nervous system nerve receptors through reversible mechanisms based on chemical principles. Positive charges on ligands are attracted to negative charges on receptors, and vice-versa.*

Envision the keyhole on your car, to understand how ligands like buprenorphine work at receptors. Your key is the ligand, and the keyhole is the receptor on the membrane of a nerve cell. Here are three (3) scenarios:

1. Agonists – If your key is an ‘agonist’ similar to oxycodone or methadone, you can insert it into the lock and turn it fully to unlock all of the doors.

2. Partial agonists – A ‘buprenorphine key’ may enter the keyhole but only turn part of the way, enough to unlock only one door. That buprenorphine key then prevents a full agonist key from unlocking the rest of the doors.

3. Antagonists – On the other hand, if an antagonist key would be inserted, it doesn’t turn to unlock any doors. Rather, an antagonist (like naltrexone) prevents any other keys from acting at the receptor.

Buprenorphine as a ligand

Ligands compete for binding at receptors. Some ligands match up so closely that they effectively out-compete other drugs for actions at the receptor. Some ligands do not match up as well, so their effects require higher concentrations at the receptor in order to compete with other ligands.

Questions about buprenorphine action

Do you still have questions about how buprenorphine works? Please leave your questions in the comments section below. We try to respond to all questions personally and promptly.

* Other types of reversible chemical interactions contribute to the tightness of the bond between ligand and receptor. When the three-dimensional structure of a molecule has attachment points that pair up perfectly with a given receptor, the molecule may bind tightly enough to prevent other ligands from binding at the receptor.
About the author
Dr. Jeffrey Junig, MD, PhD is a psychiatrist practicing in northeast Wisconsin, in recovery from opioid dependence. He is Board Certified in both Psychiatry and Anesthesiology and holds a PhD in Neuroscience. He writes about buprenorphine at Suboxone Talk Zone, and manages a forum for patients taking buprenorphine called SuboxForum.
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