title: Acute administration of THC impairs spatial but not associative memory function in zebrafish.
abstract: BACKGROUND
  The present study examined the effect of acute administration of endocannabinoid receptor CB1 ligand ∆-9-tetrahydrocannabinol (THC) on intracellular signalling in the brain and retrieval from two different memory systems in the zebrafish (Danio rerio).
  
  
  METHODS
  First, fish were treated with THC and changes in the phosphorylation level of mitogen-activated protein (MAP) kinases Akt and Erk in the brain were determined 1 h after drug treatment. Next, animals of a second group learned in a two-alternative choice paradigm to discriminate between two colours, whereas a third group solved a spatial cognition task in an open-field maze by use of an ego-allocentric strategy. After memory acquisition and consolidation, animals were pharmacologically treated using the treatment regime as in the first group and then tested again for memory retrieval.
  
  
  RESULTS
  We found an enhanced Erk but not Akt phosphorylation suggesting that THC treatment specifically activated Erk signalling in the zebrafish telencephalon. While CB1 agonist THC did not affect behavioural performance of animals in the colour discrimination paradigm, spatial memory was significantly impaired. The effect of THC on spatial learning is probably specific, since neither motor activity nor anxiety-related behaviour was influenced by the drug treatment. That indicates a striking influence of the endocannabinoid system (ECS) on spatial cognition in zebrafish.
  
  
  CONCLUSIONS
  The results are very coincident with reports on mammals, demonstrating that the ECS is functional highly conserved during vertebrate evolution. We further conclude that the zebrafish provides a promising model organism for ongoing research on the ECS.
authors.affiliation: Department for Neuroethology and Sensory Ecology, Institute of Zoology, University of Bonn, Endenicher Allee 11-13, 53115, Bonn, Germany, truhl@uni-bonn.de.
authors.forename: Tim
authors.initials: T
authors.lastname: Ruhl
authors.forename: Nicole
authors.initials: N
authors.lastname: Prinz
authors.forename: Nadine
authors.initials: N
authors.lastname: Oellers
authors.forename: Nathan Ian
authors.initials: NI
authors.lastname: Seidel
authors.forename: Annika
authors.initials: A
authors.lastname: Jonas
authors.forename: Onder
authors.initials: O
authors.lastname: Albayram
authors.forename: Andras
authors.initials: A
authors.lastname: Bilkei-Gorzo
authors.forename: Gerhard
authors.initials: G
authors.lastname: von der Emde
mesh_terms: D000818:Animals; D001921:Brain / Q000187:drug effects / Q000378:metabolism; D063386:Cannabinoid Receptor Agonists / Q000378:metabolism / Q000494:pharmacology*; D003071:Cognition / Q000187:drug effects / Q000502:physiology; D013759:Dronabinol / Q000008:administration & dosage* / Q000378:metabolism; D005260:Female; D008297:Male; D018782:Maze Learning / Q000187:drug effects; D008568:Memory / Q000187:drug effects* / Q000502:physiology; D010775:Photic Stimulation / Q000379:methods; D043884:Receptor, Cannabinoid, CB1 / Q000819:agonists / Q000378:metabolism; D013037:Spatial Behavior / Q000187:drug effects* / Q000502:physiology; D015027:Zebrafish
chemical_list: D063386:Cannabinoid Receptor Agonists; D043884:Receptor, Cannabinoid, CB1; D013759:Dronabinol