Can you guys tell me is this quote is true ? Are kappa receptors up-regulated in addiction and depression ?
"BDNF definitely plays a role. When euphoric drugs are used BDNF is released in the reward centers, I believe it's called "sensitization". Now, that might sound good, but it's actually bad. Your reward centers are basically "learning" the reward. It's why if you give a BDNF antagonist to a drug addicted animal they will become happy again. It inhibits you from learning the reward. There's other factors of course, like receptor down-regulation and kappa up-regulation, and their all interconnected. BDNF can also cause you to "learn" from stress, which is why people with high BDNF can't handle as much stress. The reason why you probably "learn" rewards is because it makes you less likely to keep doing the same thing over and over again, and more likely to try to aim higher. If gaining a dollar always gave the same pleasure, you would never make big money. But if you gain a tolerance to the pleasure of making money, you need more and more. This works in all aspects of human life. From mate choice, to status, everything. We become habituated so that we strive for more, which is good for our children. The reason BDNF changes the brain with stress is because if you're socially defeated and you act like nothing happened, that can get you killed. If you act mopey and depressed, your not seen as a threat anymore, for instance."
