Chlorpheniramine facilitates inhibitory avoidance in teleosts submitted to telencephalic ablation

Abstract

The present study investigated the involvement of H(1) histaminegic receptor on the acquisition of inhibitory avoidance in Carassius auratus submitted to telencephalic ablation. The fish were submitted to telencephalic ablation 5 days before the experiment. The inhibitory avoidance procedure included 1 day for habituation, 3 days for training composed of 3 trials each (1st day: T1, T2, T3; 2nd day: 2T1, 2T2, 2T3; 3rd day: 3T1, 3T2, 3T3) and 1 day for test. On training days, the fish were placed in a white compartment, after 30 s the door was opened. When the fish crossed to a black compartment, a weight was dropped (aversive stimuli). Immediately after the third trial, on training days, the fish received, intraperitoneally, one of the pharmacological treatments (saline (N = 20), 8 (N = 12) or 16 (N = 13) µg/g chlorpheniramine, CPA). On the test day, the time to cross to the black compartment was determined. The latency of the saline group increased significantly only on the 3rd trial of the 2nd training day (mean ± SEM, T1 (50.40 ± 11.69), 2T3 (226.05 ± 25.01); ANOVA: P = 0.0249, Dunn test: P < 0.05). The group that received 8 µg/g CPA showed increased latencies from the 2nd training day until the test day (T1 (53.08 ± 17.17), 2T2 (197.75 ± 35.02), test (220.08 ± 30.98); ANOVA: P = 0.0022, Dunn test: P < 0.05)). These results indicate that CPA had a facilitating effect on memory. We suggest that the fish submitted to telencephalic ablation were able to learn due to the local circuits of the mesencephalon and/or diencephalon and that CPA interferes in these circuits, probably due an anxiolytic-like effect.

L-histidine reduces inhibitory avoidance in Carassius auratus submitted to cerebellar ablation

“…Similar findings have been reported in several other studies (10,11,17,18). Thus, we believe that the results for the fish in the A-SAL and S-SAL groups were opposite in terms of memory consolidation of the inhibitory avoidance task due to the absence of cerebellar modulation in limbic structures in the ablation group, especially in the MP, which is thought to be homologous to the amygdala (29)(30)(31).…”

“…In this procedure, learning is inferred when the animal reduces its preference for dark places, which is an innate behavior of the species (16), associating the black compartment with an aversive experience. Several studies have used this model to investigate the action of different drugs on learning and memory processes and on processes of functional recovery in goldfish, indicating that the model is appropriate for this purpose (11,17,18).…”

“…Cofiel and Mattioli (10) have suggested that the H 2 receptor antagonist zolantidine impairs inhibitory avoidance learning and memory in goldfish. Faganello and Mattioli (11) reported that chlorpheniramine facilitates inhibitory avoidance in goldfish submitted to telencephalic ablation.…”

L-histidine provokes a state-dependent memory retrieval deficit in mice re-exposed to the elevated plus-maze

“…The action of histamine (HA) is mediated by at least four types of receptors denoted H 1 , H 2 , H 3 , and H 4 (2). Studies have indicated the importance of the neural histaminergic system (NHS) in animal behaviors, primarily anxiety (3), learning and memory (4,5). Recent reports have also provided some insight about the involvement of the NHS in Alzheimer's disease (6,7) and state-dependent memory (8).…”

Efeitos Do Clonazepam Na Esquiva Inibitória No Peixe-Dourado (Carassius Auratus)

“…Em estudos com peixes, um modelo de ansiedade que vem sendo utilizado é o modelo de esquiva inibitória (Faganello & Mattioli, 2008;Garção & Mattioli, 2009). Esse modelo é baseado na preferência por ambientes escuros e aversão a ambientes claros que diversas espécies de peixes teleósteos apresentam (Gouveia Jr. et al, 2007).…”