ABSTRACT
Aims To establish several behavioral paradigms to characterize the psychotropic effects of hallucinogens which ze-brafish was utilized as a model animal, and then to investigate the effects of potent hallucinogenic drugs on these models. Methods With the video record and track system, the behavior was recorded and quantified automatically. In the experiments, the bottom dwelling test, social behavior and mirror test were performed to test the hallucinogenic effects of drugs. Metham-phetamine (METH, 2 mg·L-1) and ketamine (20 mg·L-1) were selected as experimental challenges. The 30 min pre-treat-ment time was chosen based on our prior experience in zebrafish models. Results Compared to the normal group, in dwelling test, acute exposure of zebrafish to METH and ketamine de-creased transitions significantly, and in mirror reflection test, the drug-treated fish changed the preference for mirror zone, and ex-hibited aggressive for their mirror images. The pretreatment of METH and ketamine significantly reduced the contact durations, and the ketamine inhibited the contact frequency each other, the results indicated that the social interaction of zebrafish was im-paired. Conclusion The results confirm high sensitivity of ze-brafish models to hallucinogenic compounds with complex behav-ioral and physiological effects.
ABSTRACT
We tested the effect of social isolation on the aggressiveness of an Amazonian fish: Astronotus ocellatus. Ten juvenile fishes were transferred from a group aquarium (60 x 60 x 40 cm) containing 15 individuals (without distinguishing sex) to an isolation aquarium (50 x 40 x 40 cm). Aggressiveness was tested by means of attacks on and displays toward the mirror image. The behavior was video-recorded for 10 min at a time on 4 occasions: at 30 min, 1 day, 5 days and 15 days after isolation. The aggressive drive was analyzed in three ways: latency to display agonistic behavior, frequency of attacks and specific attacks toward the mirror image. The latency to attack decreased during isolation, but the frequency of mouth fighting (a high aggressive attack) tended to increase, indicating an augmented aggressive drive. Our findings are congruent with the behavior of the juvenile cichlid, Haplochromis burtoni but differ from the behavior observed in another cichlid, Pterophylum scalare. Increased aggressiveness in A. ocellatus may be mediated by means of the primer effect, the effect of prior residence or processes involving recognition of a conspecific.
Testamos o efeito do isolamento social sobre a agressividade no peixe amazônico, Astronotus ocellatus. Dez peixes juvenis foram transferidos de um aquário de agrupamento (60 x 60 x 40 cm) contendo 15 indivíduos (sem discriminação de sexo) para um aquário de isolamento (50 x 40 x 40 cm). A agressividade foi testada por meio de ataques e exibições direcionadas à imagem do peixe no espelho. O comportamento foi filmado durante 10 min em 4 momentos: 30 min, 1 dia, 5 dias e 15 dias após o isolamento. Nós analisamos a motivação agressiva por meio da latência para início do comportamento agonístico e pela freqüência dos ataques totais e específicos direcionados ao espelho. A latência para o comportamento agonístico reduziu ao longo do isolamento e houve uma tendência de aumento da freqüência de "mouth fighting" (um ataque de alta intensidade de agressão), mostrando-nos um aumento na motivação agressiva. Os resultados estão de acordo com os encontrados para ciclídeos juvenís de Haplochromis burtoni, mas discordam com os encontrados para Pterophylum scalare (acará bandeira). Sugerimos que o aumento da agressividade em A. ocellatus pode ser mediado pelo efeito de exposição prévia, da residência prévia ou por processos envolvendo reconhecimento de co-específicos.