The effects of the H1 antagonist chlorpheniramine on anxiety in zebrafish
anxiety, chlorpheniramine, Danio rerio, shoaling
Zebrafish (Danio rerio) have recently emerged as an excellent model organism to study the neurological basis of anxiety disorders. They display robust behavioural responses to external stimuli and possess all of the main vertebrate neurotransmitters. Research in rats has demonstrated that the histaminergic system plays a role in anxiety, possibly by interacting with other monoamines such as serotonin and dopamine. In zebrafish, however, the histaminergic system is not well characterized, so it is of interest to assess the role of histamine on anxiety in zebrafish. Chlorpheniramine, a histamine antagonist that has been tested multiple times in rodents and shown to decrease anxiety, was administered to fish with the expectation that we would observe similar anxiolytic effects in zebrafish. Chlorpheniramine was administered through immersion for ten minutes at two doses (20mg/L and 25mg/L), and zebrafish were tested using the shoaling test, which is a measure of anxiety based on the tendency of fish to form more cohesive shoals when anxious. We found that chlorpheniramine did not produce a significant anxiolytic effect at either dose; however previous research in our lab suggests that the 20mg/L dose reduces anxiety in the novel tank diving test. Further research using different doses and tests or other histamine antagonists should be conducted for a more thorough understanding of the histaminergic system in zebrafish.
Presented on April 23, 2018 at Student Research Day held at MacEwan University in Edmonton, Alberta.
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