Classification of opioids on the basis of change in seizure threshold in rats

Science  26 Oct 1979:
Vol. 206, Issue 4417, pp. 465-467
DOI: 10.1126/science.504986


Twenty opioids have been subdivided into four classes by using flurothyl-induced seizures in rats to measure dose-response relationships, stereospecificity, naloxone sensitivity, and tolerance-cross-tolerance. The data support current theories of multiple opiate receptor types. Since the receptors involved mediate effects that are antagonized, enhanced, or unaffected by naloxone, the model is uniquely suitable for detecting novel narcotic antagonists that can then be used to differentiate opiate receptors in other systems.