Neuropeptide Y Stimulates Food Intake in the Zebrafish, Danio rerio

Abstract

Neuropeptide Y (NPY) is a potent orexigenic neuropeptide implicated in feeding regulation in mammals. However, except for the case of the goldfish, the involvement of NPY in the feeding behaviour of teleost fish has not well been studied. Therefore, we investigated the role of NPY in food intake using a zebrafish (Danio rerio) model because the molecular bases of NPY and its receptor have been well studied in this species. We examined the effect of feeding status on NPY-like immunoreactivity and the expression level of the NPY transcript in the brain. The number of neuronal cells showing NPY-like immunoreactivity in the hypothalamic regions, including the periventricular nucleus of posterior tuberculum and the posterior tuberal nucleus, was significantly increased in fish fasted for 7 days. NPY mRNA levels in the hypothalamus, but not the telencephalon, obtained from fish fasted for 7 days were higher than those in fish that had been fed normally. We then investigated the effect of i.c.v. administration of NPY on food intake. Cumulative food intake was significantly increased by i.c.v. administration of NPY (at 1 and 10 pmol/g body weight; BW) during a 60-min observation period. The NPY-induced orexigenic action (at 10 pmol/g BW) was blocked by treatment with a NPY Y1 receptor antagonist, BIBP-3226, at 100 pmol/g BW. These results indicate that NPY acts as an orexigenic factor in the zebrafish.

Enhancer turnover and conserved regulatory function in vertebrate evolution

“…In fish, there is abundant evidence that POMC melanocortin peptides and AgRP also control energy balance [77,78,[82][83][84][85]. Not everything is conserved, though: while the mouse POMC neurons coexpress the neuropeptide CART, and AgRP is coexpressed with NPY, in zebrafish neither CART nor NPY is expressed in the NLT [86,87].…”

Organization of the Orexin/Hypocretin System in the Brain of Holostean Fishes: Assessment of Possible Relationships with Monoamines and Neuropeptide Y

“…In teleosts, however, OX-ir cells show restricted localizations of the basal hypothalamus, i.e., the anterior hypothalamus and lateral to the posterior tuberal nucleus of zebrafish [Kaslin et al, 2004;Faraco et al, 2006], the nucleus lateralis tuberis of the anterolateral hypothalamus and the nucleus posterioris periventricularis of the goldfish, and the cichlid Cichlasoma dimerus [Huesa et al, 2005;Pérez Sirkin et al, 2013], exclusively in the nucleus lateralis tuberis of Pygocentrus nattereri [Suzuki and Yamamoto, 2013], and in the nucleus posterioris periventricularis of medaka [Amiya et al, 2007]. Of note, some studies reveal the increase in levels of the orexin precursor mRNA in the posterior tuberal nucleus of zebrafish and winter flounder after fasting for 7-14 days [Novak et al, 2005;Buckley et al, 2010] as well as an increase in the number of orexinergic cells in the same nucleus [Yokobori et al, 2012], which allows us to relate the posterior tuberal nucleus to food intake behavior, a function that might also be shared by the basal hypothalamic OX-ir cells of holosteans.…”

Anatomical and functional analysis of non-retinal tectal afferents in larval zebrafish

“…Given the diverse roles for the hypothalamus including arousal (Prober et al, 2006;Chiu and Prober, 2013), the detection of prey (Filosa et al, 2016) and feeding (Yokobori et al, 2011;Nishiguchi et al, 2012;Yokobori et al, 2012) it seems likely that these inhibitory signals may provide some sort of modulatory effect, conceivably influencing approach/escape decisions or other behavioural calculations being carried out by tectal circuits (Barker and Baier, 2015;Bianco and Engert, 2015). The anatomy of these projections appears to be conserved with those described by Kaslin et al (2004), who show that Orexin/Hypocretin expression in the tectal neuropil is confined to the SAC in adult zebrafish.…”

“…Nonetheless, hypothalamic input appears to be modest in magnitude, and is exclusively inhibitory. Given the diverse roles for the hypothalamus including arousal (Prober et al, 2006;Chiu and Prober, 2013) and feeding (Yokobori et al, 2011;Nishiguchi et al, 2012;Yokobori et al, 2012), it seems likely that these inhibitory signals may provide some sort of modulatory effect, conceivably influencing approach/escape decisions or other behavioural calculations being carried out by tectal circuits (Barker and Baier, 2015;Bianco and Engert, 2015).…”

“…Populations of dopaminergic hypothalamic neurons have been shown to regulate light seeking and motor behaviours (Fernandes et al, 2012;McPherson et al, 78 | P a g e 2016), feeding (Yokobori et al, 2011;Yokobori et al, 2012) and sleep cycles (Chiu and Prober, 2013). Additionally, serotonergic neurons in the Raphe nucleus, which are targeted by hypothalamic neurons, have been shown to work with visual information to mediate the classification of visual stimuli as either appetitive or predatory based on the feeding state of an individual animal (Filosa et al, 2016).…”