Ghrelin Mediates Anticipation to a Palatable Meal in Rats

Abstract

Food anticipatory activity (FAA) is displayed in rats when access to food is restricted to a specific time frame of their circadian phase, a behavior thought to reflect both hunger and the motivation to eat. Rats also display FAA in a feeding schedule with ad libitum access to normal chow, but limited availability of a palatable meal, which is thought to involve mainly motivational aspects. The orexigenic hormone ghrelin has been implicated in FAA in rodents with restricted access to chow. Because ghrelin plays an important role not only in the control of food intake, but also in reward, we sought to determine the role of ghrelin in anticipation to a palatable meal. Plasma ghrelin levels of non‐restricted rats that anticipated chocolate correlated positively with FAA and were increased compared with chow‐fed control rats. Furthermore, centrally injected ghrelin increased, whereas an antagonist of the ghrelin receptor decreased, the anticipation to chocolate. Therefore, we hypothesize that central ghrelin signaling is able to mediate the motivational drive to eat.

Motivation to obtain a food reward of pregnant ewes in negative energy balance: Behavioural, metabolic and endocrine considerations

“…Ghrelin is also secreted in anticipation of a meal in sheep (Sugino et al 2002(Sugino et al , 2004. In rats, intracerebroventricular ghrelin injection increases anticipatory behaviour for a palatable chocolate reward (Merkestein et al, 2012). Feed restricted rats treated with ghrelin are also willing to press a bar more often to obtain food pellets compared to saline treated rats (King et al, 2011).…”

Physical activity: benefit or weakness in metabolic adaptations in a mouse model of chronic food restriction?

“…FRW mice developed a light period activity close to the feeding time. This activity, usually called FAA, was also described in the ABA paradigm (23,48,49,68). The FAA is usually described 2-3 h before food distribution.…”

Adaptation to short photoperiods augments circadian food anticipatory activity in Siberian hamsters

“…A mechanistic examination of photoperiodic differences in the role of orexigenic peptides in the induction of FAA was beyond the scope of the present study, but differences in the neuroendocrine sequelae of acute food deprivation also appear unlikely to explain the observed effect of photoperiod on FAA. For example, episodic ghrelin signaling is sufficient to drive FAA in rats (Merkestein et al, 2012), but photoperiod does not affect ghrelin responses to food deprivation in Siberian hamsters (Tups et al, 2004b). Changes in sensitivity to ghrelin also seem unlikely to explain different FAA in SD compared to LD: consummatory responses to ghrelin are markedly greater in LD relative to SD (Bradley et al, 2010).…”