knockout mouse Animals 92 nonhuman 90 mouse 84 Mice 78 Mice, Knockout 78 priority journal 74 controlled study 68 animal 58 animal experiment 54 animal tissue 50 male 48 genetics 44 animal cell 42 female 42 metabolism 42 article 40 Male 38 Article 34 Female 30 Receptors, Dopamine D2 28 dopamine 2 receptor 28 physiology 28 protein expression 28 animal model 26 Humans 24 human 24 unclassified drug 24 genotype 22 signal transduction 20