Figure 1From: Genetic polymorphisms in monoamine neurotransmitter systems show only weak association with acute post-surgical pain in humansMaximum post-operative pain ratings and SNPs from COMT and MAOA. COMT: catechol O-methylatransferase gene MAOA: monoamine oxidase A gene, females only *, p < 0.05 **, p < 0.01Back to article page