Molecular Biology of Opioid Analgesia Gavril W. Pasternak, MD, PhD  Journal of Pain and Symptom Management  Volume 29, Issue 5, Pages 2-9 (May 2005) DOI: 10.1016/j.jpainsymman.2005.01.011 Copyright © 2005 U.S. Cancer Pain Relief Committee Terms and Conditions

Fig. 1 Sensitivity of CD-1 and CXBK mice to μ opioids. Mice were administered doses of the indicated drugs that were adjusted to produce a similar analgesic effect in CD-1 mice. The same doses were then given to the CXBK mice. Data from Rossi et al.15 and Pasternak.2 Journal of Pain and Symptom Management 2005 29, 2-9DOI: (10.1016/j.jpainsymman.2005.01.011) Copyright © 2005 U.S. Cancer Pain Relief Committee Terms and Conditions

Fig. 2 Incomplete cross-tolerance to morphine by μ opioids. Mice were administered doses of the indicated drugs that were adjusted to produce a similar analgesic effect in naïve CD-1 mice. The same doses were then given to the mice after five daily doses of morphine. Data from Rossi et al.15 Journal of Pain and Symptom Management 2005 29, 2-9DOI: (10.1016/j.jpainsymman.2005.01.011) Copyright © 2005 U.S. Cancer Pain Relief Committee Terms and Conditions

Fig. 3 Mu opioid analgesia in an exon 1 MOR-1 knockout mouse. Morphine, morphine-6β-glucuronide (M6G) or heroin were given at the stated dosed to the wildtype or knockout mice. Data from Schuller et al.30 Journal of Pain and Symptom Management 2005 29, 2-9DOI: (10.1016/j.jpainsymman.2005.01.011) Copyright © 2005 U.S. Cancer Pain Relief Committee Terms and Conditions

Fig. 4 Schematic of the μ opioid receptor gene Oprm and the MOR-1 splice variants. Schematic of the structure of the Oprm gene and the identified splice variants of the mouse μ opioid receptor. Compiled from Pick et al.,17 Moskowitz and Goodman,18 and Pasternak.19 Journal of Pain and Symptom Management 2005 29, 2-9DOI: (10.1016/j.jpainsymman.2005.01.011) Copyright © 2005 U.S. Cancer Pain Relief Committee Terms and Conditions