The Effects of the H1 Histamine Antagonist Chlorpheniramine on Reinforcement, Learning and Memory in Goldfish, Carassius auratus

• Main Author: Nelson, Carrie A
• Format: Others
• Published: NSUWorks 1997
• Subjects: Marine Biology; Oceanography and Atmospheric Sciences and Meteorology
• Online Access: http://nsuworks.nova.edu/occ_stuetd/326; http://nsuworks.nova.edu/cgi/viewcontent.cgi?article=1069&context=occ_stuetd

The purpose of this study was to examine central effects of H1 histamine receptor antagonist, CPA on a fish. A two part study was conducted using goldfish, Carassius auratus. The first study consisted of examining the reinforcing effects of CPA on behavior. The hypothesis for this experiment is that CPA has a positive effect on reinforcement. That is, that CPA, when administered to goldfish, can reinforce a specific behavioral response. The behavior response was tested by the preference for either a white or black compartment in an aquarium. The test method consisted of 1) habituating fish to the experimental tank in a 20 min session; 2) 24 h later, establishing the less preferred of two compartments for each fish in a 10 min test; 3) confining each fish, 24h later, in the less preferred compartment for 25 min after an i.p injection of either one of the four doses of CPA 0.1,0.4,1.0,4.0 mg/kg of body weight or vehicle control (n=18 for each group); 4) reexamining the behavioral preference, 24 h after injection, in a second 10 min test. Analysis of results found a significant difference between compartment preference before and after treatment (KWANOVA, p=0.00027). Groups that received 1.0 and 4.0 mg/kg of CPA spent significantly more time in the drug paired compartment, while the group that received 0.4 mg/kg of CPA spent less (SNK, p<0.05). These findings support the hypothesis that CPA can act as a reinforcing agent in goldfish and it appears the histaminergic system may have an inhibitory role in the reinforcing process. The hypothesis for the second experiment is that CPA can enhance learning and memory. The second study tested the effects of CPA on memory traces and learning behavior. The study consisted of two injection schedules, one of fish injected immediately after training (Immediate Group, n=36) and the other of fish injected three hours after training (Delayed Group, n=36). Fish of both injection schedules were tested in a feeding model that consisted of an experimental tank, half black and half white, with a feeder located in each compartment. The test method consisted of 1) Training Day. A food pellet was placed in the feeder in one of the tank's compartments, either black or white. Fish were allowed to explore the tank until food was located and eaten or until 10 min had elapsed. Time to begin feeding was recorded. Fish were then injected i.p. with either vehicle (n=18) or 1.0 mg/kg of body weight of CPA (n=18) either immediately or 3 hours post training; 2) Test Day. 24 h later, a food pellet was placed on the same side as the Training Day. Fish were allowed to explore the tank until the food was located and eaten. Time to begin feeding was recorded; 3) Reversion Test Days 1-4. Four days of reversal procedure were tested 24 h apart. Fish were tested in the same fashion, but the location of the food pellet was reversed. On the Test Day the time to begin feeding for vehicle injected fish was significantly greater than those injected with CPA (MW, p=0.0112). Similarly, the vehicle group took longer to begin feeding than the CPA group on the first Reversion Test Day (MW, p=0.0261). Subsequent reversion session did not show any significant difference (MW, p>0.05). With the Delayed Group although there was a significant difference among experiment sessions (ANOVA, p=1.23E-0I5), there was not a difference between drug and vehicle (ANOVA, p=0.68). Multiple comparisons revealed there was no significant difference between vehicle and drug for any experimental session (MW, p>0.05). These results suggest that CPA can affect learning and memory. The results of the Immediate Group compared to the Delayed Group indicate that the mechanism of enhancement occurs before memory consolidation is final. Taken together these two studies indicate that CPA has not only a reinforcing effect in goldfish, but also has the ability to improve learning and memory.