Morphine-induced anti-nociception and reward in "humanized" mice expressing the mu opioid receptor A118G polymorphism.

Morphine-induced anti-nociception and reward in "humanized" mice expressing the mu opioid receptor A118G polymorphism. Brain Res Bull. 2015 Oct 28; Authors: Henderson-Redmond AN, Yuill MB, Lowe TE, Kline AM, Zee ML, Guindon J, Morgan DJ Abstract The rewarding and anti-nociceptive effects of opioids are mediated through the mu-opioid receptor. The A118G single-nucleotide polymorphism in this receptor has been implicated in drug addiction and pain. Clinical and preclinical studies have found that the G allele is associated with increased heroin reward and self-administration, elevated post-operative pain, and reduced analgesic responsiveness to opioids. Male and female mice homozygous for the "humanized" 118AA or 118GG alleles were evaluated to test the hypothesis that 118GG mice are less sensitive to the rewarding and anti-nociceptive effects of morphine. We found that 118AA and 118GG mice of both genders developed conditioned place preference for morphine. All mice developed tolerance to the acute anti-nociceptive and hypothermic effects of morphine. However, morphine tolerance was not different between AA and GG mice. We also examined sensitivity to the acute anti-nociceptive and hypothermic effects of cumulative morphine doses. We don't find any gender or genotype differences in the cumulative dose response effects for morphine. Finally, we examined basal pain response and morphine-induced anti-nociception in the formalin test for ...
Source: Brain Research Bulletin - Category: Neurology Authors: Tags: Brain Res Bull Source Type: research