title: Dopamine receptors participate in acquisition and consolidation of latent learning of spatial information in zebrafish (Danio rerio).
abstract: There is growing appreciation that various aspects of learning and memory are strongly influenced by dopamine neurotransmission, and that zebrafish hold particular promise in the study of neurotransmitter systems. In this study, we sought to investigate the effect of dopamine receptors on acquisition and consolidation of memory in zebrafish using a latent learning paradigm. To this end, fish were subjected to a 30 min training trial each day for 16 days during which fish were allowed to freely explore a complex maze with the left or right path blocked and without the presence of a reward. During 16 days fish were treated with dopaminergic agonists (apomorphine, SKF-38393, and quinpirole) and antagonists (SCH-23390 and eticlopride) before or after training trials. To assess cognitive performance of fish, a subsequent probe trial was performed on day 17 while all paths leading to a reward chamber were open and the maze now contained stimulus fish as a reward. Pre- and post-training exposure to apomorphine, SKF-38393, and quinpirole significantly impaired learning and memory in fish. In contrast, fish exposed to eticlopride before and after training exhibited improved performance in a latent learning task. Administration of SCH-23390 before training did not affect zebrafish learning ability, but produced significant memory enhancement when given after training trials. Taken together, these findings are the first indications that D1 and D2 receptors are critically involved in acquisition and consolidation of latent learning in zebrafish, with a more prominent role for D2 receptors. The current study opens the door to future studies to investigate the involvement of dopamine receptors in various aspects of cognitive processes.
authors.affiliation: Department of Biology, University of Saskatchewan, 112 Science Place, Saskatoon, SK S7N 5E2, Canada. Electronic address: mohammad.naderi@usask.ca.
authors.forename: Mohammad
authors.initials: M
authors.lastname: Naderi
authors.affiliation: Department of Biology, University of Saskatchewan, 112 Science Place, Saskatoon, SK S7N 5E2, Canada.
authors.forename: Ankur
authors.initials: A
authors.lastname: Jamwal
authors.affiliation: Department of Veterinary Biomedical Sciences, University of Saskatchewan, 52 Campus Drive, Saskatoon, SK S7N 5B4, Canada.
authors.forename: Maud C O
authors.initials: MC
authors.lastname: Ferrari
authors.affiliation: Department of Biology, University of Saskatchewan, 112 Science Place, Saskatoon, SK S7N 5E2, Canada; Toxicology Centre, University of Saskatchewan, 44 Campus Drive, Saskatoon, SK S7N 5B3, Canada.
authors.forename: Som
authors.initials: S
authors.lastname: Niyogi
authors.affiliation: Department of Biology, University of Saskatchewan, 112 Science Place, Saskatoon, SK S7N 5E2, Canada.
authors.forename: Douglas P
authors.initials: DP
authors.lastname: Chivers
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D015259:Dopamine Agents / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D005260:Female; D008297:Male; D018782:Maze Learning / Q000187:drug effects; D011954:Receptors, Dopamine / Q000378:metabolism*; D065853:Spatial Learning / Q000187:drug effects / Q000502:physiology*; D065852:Spatial Memory / Q000187:drug effects / Q000502:physiology*; D013997:Time Factors; D015027:Zebrafish
chemical_list: D015259:Dopamine Agents; D011954:Receptors, Dopamine
keywords: D1 receptor; D2 receptor; Latent learning; Spatial exploration; Zebrafish