Daily Scheduled High Fat Meals Moderately Entrain Behavioral Anticipatory Activity, Body Temperature, and Hypothalamic c-Fos Activation

Abstract

When fed in restricted amounts, rodents show robust activity in the hours preceding expected meal delivery. This process, termed food anticipatory activity (FAA), is independent of the light-entrained clock, the suprachiasmatic nucleus, yet beyond this basic observation there is little agreement on the neuronal underpinnings of FAA. One complication in studying FAA using a calorie restriction model is that much of the brain is activated in response to this strong hunger signal. Thus, daily timed access to palatable meals in the presence of continuous access to standard chow has been employed as a model to study FAA in rats. In order to exploit the extensive genetic resources available in the murine system we extended this model to mice, which will anticipate rodent high fat diet but not chocolate or other sweet daily meals (Hsu, Patton, Mistlberger, and Steele; 2010, PLoS ONE e12903). In this study we test additional fatty meals, including peanut butter and cheese, both of which induced modest FAA. Measurement of core body temperature revealed a moderate preprandial increase in temperature in mice fed high fat diet but entrainment due to handling complicated interpretation of these results. Finally, we examined activation patterns of neurons by immunostaining for the immediate early gene c-Fos and observed a modest amount of entrainment of gene expression in the hypothalamus of mice fed a daily fatty palatable meal.

Sex-related difference in food-anticipatory activity of mice

“…reduced availability of food (Gallardo et al, 2012;Hampstead et al, 2003;Szentirmai et al, 2010). Thus, we examined whether there were differences in food consumption and body weight between male and female mice under RF conditions.…”

“…Animals display a variable intensity of FAA in association with different feeding cycles (Mistlberger and Marchant, 1995;Stephan and Becker, 1989). In addition, a high-fat diet and diabetes result in dampened FAA in anticipation of daily meals under RF conditions, suggesting that the intensity of FAA is closely related to energy storage and expenditure (Gallardo et al, 2012;Persons et al, 1993).…”

Long-term High-Soybean Oil Feeding Alters Regulation of Body Temperature in Rats

“…18,20,34,35) In studies when BT was measured after high-fat dietary intervention, either an increase or no change in BT have both been observed. 16,[19][20][21]36,37) Our results show that HSD and HLD produced hypothermia, whereas HFD did not influence BT. These inconsistent results are likely to be brought from the different kinds and content of fatty acids in the diets that influence biosynthesis and secretion of adipokines or lipid mediators, and characteristics of the cell membrane.…”

“…[15][16][17][18] However, when BT is actually measured during intervention of high-fat diet, various results on BT, hyperthermia, hypothermia or no changes, are reported. 5,16,[19][20][21] As one of the reasons of the inconsistent results, the differences among experimental conditions, such as kinds of high-fat diets and feeding period, are raised. In this study, we used three kinds of high-fat diet, and investigated effects of dietary fat on BT regulation.…”

Chrono-biology, Chrono-pharmacology, and Chrono-nutrition

“…A palatable snack (chocolate) in the daytime also elicited FAA and c-Fos expression in the corticolimbic area (181), and this entrainment is thought to be mediated by ghrelin (182). Scheduled access to high-fat chow ad libitum caused FAA and c-Fos activation in the hypothalamus (183). These results suggest that glucose or a palatable snack can induce the FEO.…”