THE FOOD-ENTRAINABLE OSCILLATOR: A NETWORK OF INTERCONNECTED BRAIN STRUCTURES ENTRAINED BY HUMORAL SIGNALS?

Abstract

Food is critical for all animal species. Its temporal availability is a relevant signal for organizing behavioral and physiological parameters. When food is restricted to a few hours per day, rats, mice, and other mammals exhibit anticipatory activity before mealtime (food-anticipatory activity). There is considerable evidence suggesting that this anticipation is mediated by a food-entrainable oscillator (FEO) with circadian properties, but located outside the suprachiasmatic nucleus of the hypothalamus (the light-entrainable oscillator). However, the locus of the FEO as well as the mechanisms by which food entrainment occurs is unclear. In this review, we summarize data about the potential input pathways to the FEO and propose a model for understanding it as a network of interconnected brain structures entrained by fluctuation of different humoral signals. (Author correspondence: [email protected]).

Key Words:

• Food entrainment
• Circadian rhythm
• Food-anticipatory activity
• Food-entrainable oscillator
• Humoral pathway

ACKNOWLEDGMENTS

We thank Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq), Pró-reitoria de Pesquisa da Universidade Federal do Rio Grande do Norte (PROPESQ-UFRN), Fundação de Amparo à Pesquisa do Estado do Rio Grande do Norte (FAPERN), and Graduate Student Exchange Program (GSEP) from the Canadian government for financial support. We also thank three anonymous reviewers for relevant comments and suggestions, and Margaret M. Koletar for suggestions and her review of the writing.

The authors declare no conflicts of interest. The authors alone are responsible for the content and writing of the paper.