The peripherally restricted opioid receptor antagonist naloxone methiodide reverses fentanyl-induced respiratory depression without causing aversive behaviors that are observed after naloxone.

Reversing opioid overdoses in rats using a drug that does not enter the brain prevents the sudden and severe withdrawal symptoms associated with therapeutics that target the central nervous system.

Opioid sensitive neurons were identified using a traceless affinity labeling strategy to covalently label endogenous mu-opioid receptors with fluorescent compounds in living brain slices from wild type animals.

A novel opioid formulation producing analgesia similar to conventional opioids without permeation of blood-brain or intestinal barriers, thus precluding sedation, constipation and respiratory depression.

The structure-based design established a new approach to control pathway-selective activation of opioid receptors, resulting in new dual MOR/KOR G-protein biased agonist analgesics with attenuated liabilities.