Accession Number:



In Vitro Approach to Evaluating Opioid Receptor Subtype Specificity

Descriptive Note:

[Technical Report, Final Report]

Corporate Author:

Edgewood Chemical Biological Center

Report Date:


Pagination or Media Count:



Reported potencies of opioid compounds were derived from in vitro, in vivo, and ex vivo methods in various model species for all the experiments that were conducted. In this study, a human receptor-expressing cell system was used to measure the potency and efficacy of carfentanil a known ultra-potent opioid and 4-chloro-N-2Z-1-2-4-nitrophenylethylpiperidin-2-ylidenebenzene-1-sulfonamide W-18, a suspect opioid that has received much attention as a public health concern. This system demonstrated the ease and efficiency of using a set of cell-based tools to screen for opioid activity and specificity for future compounds of interest and suspect or unknown opioid or opiate compounds. Carfentanil was more specific for the -opioid receptor MOR than previously thought, but its low median effective concentration indicated that it could have off-target effects at physiologically relevant concentrations, which could potentially lead to toxicity. W-18 was inactive at all four human receptor subtypes delta-opioid receptor, kappa-opioid receptor, MOR and opioid-like receptor 1, which refutes reports that W-18 is an ultra-potent opioid 10,000 times more potent than morphine. Although this study does not account for reported toxicity, it does rule out the opioid system as the culprit receptor.


Subject Categories:

  • Pharmacology

Distribution Statement:

[A, Approved For Public Release]