Intracerebroventricular administration of sulphated cholecystokinin octapeptide induces anxiety‐like behaviour in goldfish

Abstract

Sulphated cholecystokinin octapeptide (CCK‐8s) is involved in feeding regulation as an anorexigenic neuropeptide in vertebrates. In rodents, i.c.v. administration of CCK‐8s has been shown to affect not only feeding behaviour, but also psychomotor activity. However, there is still no information available concerning the psychophysiological effects of CCK‐8s in goldfish. Therefore, in the present study, we examined the effect of synthetic goldfish (gf) CCK‐8s on psychomotor activity in this species. Intracerebroventricular administration of gfCCK‐8s at 0.1, 0.5 and 2.5 pmol g‐1 body weight (BW) did not affect swimming distance (locomotor activity). Because goldfish prefer the lower to the upper area of a tank, we used this as a preference test (upper/lower test) to assess anxiety‐like behaviour. Intracerebroventricular administration of gfCCK‐8s at 2.5 pmol g‐1 BW shortened the time spent in the upper area. The action of gfCCK‐8s mimicked that of FG‐7142 (the central‐type benzodiazepine receptor inverse agonist, an anxiogenic agent) at 5 and 10 pmol g‐1 BW. The anxiogenic‐like effect of gfCCK‐8s was abolished by treatment with the CCK receptor antagonist proglumide at 50 pmol g‐1 BW. We also investigated the localisation of CCK/gastrin‐like immunoreactivity in the goldfish brain. CCK/gastrin‐like immunoreactivity was observed in the anxiety‐related regions (the nucleus habenularis and the interpeduncular nucleus). These data indicate that gfCCK‐8s potently affects psychomotor activity in goldfish, and exerts an anxiogenic‐like effect via the CCK receptor‐signalling pathway.

Assessing Chronodisruption Distress in Goldfish: The Importance of Multimodal Approaches

“…The evaluation of scototaxis (in the black/white preference test) and thigmotaxis (in the open field test) shows the result of a conflict between the safeness that a dark area or a wall provides to the animals and their natural motivation to explore new environments [37,50]. Several fish species are known to exhibit scototaxis and thigmotaxis, including zebrafish, common carp, salmon, three-spine stickleback, Mexican blind cavefish, medaka, and goldfish [50][51][52][53][54][55][56][57], although these behaviors can vary during the earlier developmental stages [57,58]. In this work, untreated goldfish spent around 80% of their time near the walls in the OF test and 70% of their time in the black zone in the BW test, confirming the presence of these behavioral tendencies, as expected in adult goldfish.…”