The effects of epinephrine and norepinephrine on agonistic behavior in Siamese fighting fish (Betta splendens)

Abstract

The relatively stereotyped patterns of agonistic responses which are typical of many species of animals may be designated as Agonistic Fixed Action Patterns (AFAPs). In the case of the male Siamese fighting fish (Betta splendens) the AFAP, which consists of gill erection, fin erection, a deepening of coloration, frontal approach and withdrawal, is elicited by the image of a male of the species. Employing both male and female Siamese fighting fish, the present experiment sought to test the hypothesis that norepinephrine, which has been related to aggression, would increase the positive reinforcing properties of mirror image presentation, and that epinephrine, which has been related to fear, would decrease the positive reinforcing properties of this stimulus. Using a modification of the Thompson (1963) operant apparatus and procedure, the experiment was conducted in three replications with three male and three female Ss being tested in each replication. Baseline data were gathered for 12 24 hr. days. On day 13 Ss were treated with either epinephrine, norepinephrine, or a water solution in bath. On day 14 Ss were replaced into untreated water in which they remained for 48 hrs. The duration of time spent viewing the mirror image was automatically recorded during the 15 day period. Results supported the hypotheses concerning the actions of epinephrine and norepinephrine. In the case of both male and female treatment groups, norepinephrine was found to significantly increase response duration level. A lowering of response level with epinephrine treatment, although not meeting the usual criterion of statistical significance, was strongly suggested by the data. Findings were discussed in the context of fear an aggression action circuits within the CNS, and it was suggested that these circuits are differentially sensitive to epinephrine and norepinephrine, respectively. In discussing the failure to find a statistically significant epinephrine effect, I was suggested that the use of a larger number of Ss or use of response frequency instead of response duration measures may result in a statistically significant epinephrine effect upon replication.