Andrew Huberman· PhD
And dynorphin is known to negatively impact the dopamine receptor system. So, basically, it's the feel-like-garbage pathway. - Right, you feel like garbage, and so you think that that would not be good, but this is where my friend comes in. He was looking at the effects of treating morphine or heroin addiction. And people that are using those drugs, they, basically, the endorphins or the morphine or heroin, they bind to a receptor in the brain called the mu opioid receptor. And, as they take these drugs, that mu opioid receptor becomes downregulated, and so you need more and more of the drug to feel as good as you did. Well, endorphins also bind to that receptor. And he was looking into some of the other drugs that are like salvinoria, salvinorin, or something. Salvia it's called. It binds to the kappa opioid receptor. It also makes you kind of feel uncomfortable. Anyways, he had put some studies in front of me that showed basically binding of either dynorphin or whatever ligand to the kappa opioid receptor basically sensitizes the mu opioid receptor to the feel-good endorphins and also changes, I think it also upregulates it or something, so, basically, there's a lasting effect of feeling good.