21. Naloxone or naltrexone is the preferred human opioid receptor antagonist. 22. Menthol also acts as a weak kappa opioid receptor agonist. 23. Dezocine is a mixed agonist / antagonist of opioid receptors . 24. Leu-enkephalin has agonistic actions at both the ?-opioid receptor . 25. Next, he gave them a drug that blocked the opioid receptors and repeated the experiment. 26. The endogenous system of opioid receptors is well known for its analgesic potential in vertebrates. 27. He said naltrexone stops the cycle of craving by blocking what are called opioid receptors . 28. Alcohol activates endogenous opioid receptors , potentiating dopamine release which increases the rewarding effects of alcohol. 29. At the extremes of this suggestion lies the possibility of a mu-delta opioid receptor oligomer. 30. Apigenin is a antagonist of all three opioid receptors .
