title: Knockout crickets for the study of learning and memory: Dopamine receptor Dop1 mediates aversive but not appetitive reinforcement in crickets.
abstract: Elucidation of reinforcement mechanisms in associative learning is an important subject in neuroscience. In mammals, dopamine neurons are thought to play critical roles in mediating both appetitive and aversive reinforcement. Our pharmacological studies suggested that octopamine and dopamine neurons mediate reward and punishment, respectively, in crickets, but recent studies in fruit-flies concluded that dopamine neurons mediates both reward and punishment, via the type 1 dopamine receptor Dop1. To resolve the discrepancy between studies in different insect species, we produced Dop1 knockout crickets using the CRISPR/Cas9 system and found that they are defective in aversive learning with sodium chloride punishment but not appetitive learning with water or sucrose reward. The results suggest that dopamine and octopamine neurons mediate aversive and appetitive reinforcement, respectively, in crickets. We suggest unexpected diversity in neurotransmitters mediating appetitive reinforcement between crickets and fruit-flies, although the neurotransmitter mediating aversive reinforcement is conserved. This study demonstrates usefulness of the CRISPR/Cas9 system for producing knockout animals for the study of learning and memory.
authors.affiliation: Faculty of Science, Hokkaido University, Sapporo 060-0810, Japan.
authors.forename: Hiroko
authors.initials: H
authors.lastname: Awata
authors.affiliation: Department of Biological Science and Technology, Faculty of Engineering, The University of Tokushima, Tokushima 770-8506, Japan.
authors.forename: Takahito
authors.initials: T
authors.lastname: Watanabe
authors.affiliation: Faculty of Science, Hokkaido University, Sapporo 060-0810, Japan.
authors.forename: Yoshitaka
authors.initials: Y
authors.lastname: Hamanaka
authors.affiliation: Department of Biological Science and Technology, Faculty of Engineering, The University of Tokushima, Tokushima 770-8506, Japan.
authors.forename: Taro
authors.initials: T
authors.lastname: Mito
authors.affiliation: Department of Biological Science and Technology, Faculty of Engineering, The University of Tokushima, Tokushima 770-8506, Japan.
authors.forename: Sumihare
authors.initials: S
authors.lastname: Noji
authors.affiliation: Faculty of Science, Hokkaido University, Sapporo 060-0810, Japan.
authors.forename: Makoto
authors.initials: M
authors.lastname: Mizunami
mesh_terms: D000818:Animals; D001362:Avoidance Learning / Q000502:physiology*; D001522:Behavior, Animal / Q000502:physiology*; D004298:Dopamine / Q000378:metabolism; D059290:Dopaminergic Neurons / Q000378:metabolism; D006135:Gryllidae / Q000378:metabolism / Q000502:physiology*; D008568:Memory / Q000502:physiology*; D009655:Octopamine / Q000378:metabolism; D011678:Punishment; D011954:Receptors, Dopamine / Q000378:metabolism*; D012054:Reinforcement, Psychology; D012201:Reward
chemical_list: D011954:Receptors, Dopamine; D009655:Octopamine; D004298:Dopamine