Morphine tolerance in mice is independent of polymorphisms in opioid receptor sequences

Pharmacogenomics links individual drug response variation to genetic differ ences, such as single nucleotide polymorphisms (SNPs), In particular, pharm acogenomics will allow clinicians to use genetic diagnostics to predict the response of a patient to a drug. We investigated whether SNPs in opioid re ceptors correlated with the development of morphine tolerance in mouse stra ins that showed either high or low tolerance to morphine. Sequencing identi fied five silent SNPs in the delta opioid receptor that varied from the pub lished sequence in some strains, but which were found in both high and low tolerance strains, The mu and kappa opioid receptor sequences had no SNPs. Taken together, these data definitively demonstrate that morphine tolerance development in mice is independent of opioid receptor sequence. (C) 2001 E lsevier Science Inc.