Figure 1From: Combined analysis of circulating β-endorphin with gene polymorphisms in OPRM1, CACNAD2 and ABCB1 reveals correlation with pain, opioid sensitivity and opioid-related side effectsGenotype frequency of ABCB1. The genotype frequency of the ABCB1 SNP in chronic pain with different opioid sensitivity. For further details see Methods and Results.Back to article page