Eating – You, the World, and Food
Emily Crews Splane, Neil E. Rowland, Anaya Mitra in Psychology of Eating, 2019
All animals eat, and the study of feeding behavior of animals can give us important insights into human behavior. Further, for animals that have similar feeding habits to our own (i.e., mammalian omnivores, like rats), there is every reason to believe that some of the physiological and brain mechanisms underlying feeding are similar to our own. Although many aspects of feeding and the brain can be directly studied in humans, and many examples will be given in this book, there are some scientific procedures and measures that we cannot perform in humans but instead turn to suitable animal models to address the questions. Most such research uses rats or mice, and we will occasionally refer to such studies. All animal research is highly regulated and reviewed by both institutional and national professional entities with regard to rigorously humane treatment and scientific necessity. Likewise, all research with humans is regulated by institutional review boards, and includes not only aspects of safety but also confidentiality of records.
Untangling Appetite Circuits with Optogenetics and Chemogenetics
Ruth B.S. Harris in Appetite and Food Intake, 2017
Major goals in the experimental exploration of feeding behavior are initially to break down and subsequently attempt to identify the underlying mechanisms by which an animal (a) is stimulated to eat; (b) eats a fixed amount of a certain food during a meal, or bout of eating, until satiety occurs; and (c) ceases feeding behavior due to various satiety signals. This is accomplished using a variety of feeding paradigms in animal models, such as free-feeding (ad libitum), scheduled feeding, instrumental motivational feeding, and food deprivation states while recording the ensuing eating patterns. Furthermore, food palatability, external sensory cues, and learned responses all play major roles in both the attainment and ingestion of calories. The overarching complexity and multiple layers of eating behavior, in addition to increased interest from the general public at large, make understanding the molecular, cellular, and neural machinery controlling feeding imperative to both our health and curiosity. To this end, the last century has made significant progress toward this goal using a variety of approaches. For the purposes of this chapter, emphasis will be placed on real-time methods, namely, optogenetics and chemogenetics, to rapidly and reversibly tune cellular activity with unparalleled jurisdiction.
Transition from artificial enteral tube nutrition to oral eating: tube-weaning feeding therapy
Clarissa Martin, Terence Dovey, Angela Southall, Clarissa Martin in Paediatric Gastrointestinal Disorders, 2019
Behavioural approaches and specific intervention protocols to help children to develop oral eating behaviour have been extensively documented (e.g. Linscheid, 2006; Rommel et al., 2003). Sharp et al. (2010) completed a systematic review of the literature on treatment intervention for paediatric feeding disorders including 48 single case studies that reported outcomes for 96 children. They found that all studies revisited included behavioural intervention. Results indicated that behavioural intervention was associated with significant improvements in feeding behaviour. Behavioural interventions may vary from application of positive reinforcement techniques to more elaborate behavioural protocols that may include specialist shaping, fading, escape extinction procedures, and so forth (Piazza et al., 2003; Williams et al., 2007).
Interaction between central GABAA receptor and dopaminergic system on food intake in neonatal chicks: role of D1 and GABAA receptors
Published in International Journal of Neuroscience, 2018
Mona Hashemzadeh, Morteza Zendehdel, Vahab Babapour, Negar Panahi
Feeding behaviour is a complex physiologic phenomenon which interacts via diverse signals from the central and peripheral tissues [1,2]. In the central nervous system (CNS), several neurotransmitters interact by a wide distributed neurological network on food intake regulation [3]. The homeostasis of the food intake regulates by complex neurochemical mechanisms in several parts of the brain such as striatum, amygdala and hypothalamus [3]. γ-Aminobutyric acid (GABA) is an important neurotransmitter which has many physiologic actions such as anti-convulsion, pain alleviation, sleep, memory, regulation of respiration and appetite [4]. The GABAergic system acts via distinct receptors, including the GABAA, GABAB and GABAC receptors [5]. The GABAA and GABAC receptors are part of a macromolecular complex coupled to a Cl− ionophore while GABAB is a metabotropic receptor belonging to G-protein-coupled receptors (GPCRs) [6]. Intracerebroventricular (ICV) injection of GABAA and GABAB agonists increases feeding in layer [2,7] but GABAB agonist has no effect on broiler [8]. Also, the stimulatory role of GABA in the regulation of food intake was reported in the turkey [9].
Central microinjection of phytohormone abscisic acid changes feeding behavior, decreases body weight, and reduces brain oxidative stress in rats
Published in Nutritional Neuroscience, 2019
Monavereh Soti, Mehdi Abbasnejad, Razieh Kooshki, Saeed Esmaeili-Mahani
Oxidative stress, an imbalance between the oxidants and antioxidants, is a major risk factor for the induction of metabolic diseases. In a normal situation, antioxidant enzymes, such as catalases and peroxidase serve a defending role in brain via inactivation of detrimental oxidants which are produced in metabolic procedures.23 It has been indicated that nutritional treatments raise antioxidant capacity and could be helpful in suppressing clinical features of disrupted metabolism.24,25 It has been demonstrated that the critical regulatory sites for the integration of metabolic signals are brain stem regions including solitary tract, dorsal vagal complex, and diencephalon centers mainly hypothalamus nuclei.26,27 Therefore, biochemical analysis of such regions might be helpful to identify the mechanism of drugs or agents on feeding behavior.
Dietary macronutrient composition affects hypothalamic appetite regulation in chicks
Published in Nutritional Neuroscience, 2018
Betty R. McConn, Justin Matias, Guoqing Wang, Mark A. Cline, Elizabeth R. Gilbert
Dietary fat and carbohydrates also regulate short- and long-term feeding behavior in mammals. As reviewed by Morris et al.,10 elevated, chronic consumption of fats and simple sugars lead to compulsive feeding behaviors and obesity in humans, with a complex interplay between palatability, reward neurocircuitry, stress and feeding behavior, and cognition.10 In rats fed diets differing in fat composition for about 30 days, food intake increased by 4–27%, whereby emulsifying and diluting corn oil in water increased fat and total caloric intake and the rats consumed more vegetable shortening than corn oil.11 This suggests that the differential food intake was due to the physical nature of fat rather than its composition. In contrast, short-term feeding (1 week) still allows time for the animal to adjust to the new diet yet also isolates diet effects from the confounds of growth or secondary stress mechanisms. Rats fed a high-fat diet (76.8% vegetable shortening) for 1 week ate less, with a down-regulation of neuropeptide Y (NPY) mRNA in the arcuate (ARC) nucleus of the hypothalamus.12