Neuroendocrine regulation of appetitive ingestive behavior

Abstract

Food availability in nature is often irregular, and famine is commonplace. Increased motivation to engage in ingestive behaviors increases the chance of survival, providing additional potential opportunities for reproduction. Because of the advantages conferred by entraining ingestive behavior to environmental conditions, neuroendocrine mechanisms regulating the motivation to acquire and ingest food have evolved to be responsive to exogenous (i.e., food stored for future consumption) and endogenous (i.e., body fat stores) fuel availability. Motivated behaviors like eating occur in two phases. The appetitive phase brings animals into contact with food (e.g., foraging, food hoarding), and the more reflexive consummatory phase results in ingestion (e.g., chewing, swallowing). Quantifiable appetitive behaviors are part of the natural ingestive behavioral repertoire of species such as hamsters and humans. This review summarizes current knowledge about neuroendocrine regulators of ingestive behavior, with an emphasis appetitive behavior. We will discuss hormonal regulators of appetitive ingestive behaviors, including the orexigenic hormone ghrelin, which potently stimulates foraging and food hoarding in Siberian hamsters. This section includes a discussion of the hormone leptin, its relation to endogenous fat stores, and its role in food deprivation-induced increases in appetitive ingestive behaviors. Next, we discuss how hormonal regulators interact with neurotransmitters involved in the regulation of ingestive behaviors, such as neuropeptide Y (NPY), agouti-related protein (AgRP) and α-melanocyte stimulating hormone (α-MSH), to regulate ingestive behavior. Finally, we discuss the potential impact that perinatal nutrient availability can have on the neuroendocrine regulation of ingestive behavior. Understanding the hormonal mechanisms that connect metabolic fuel availability to central appetite regulatory circuits should provide a better understanding of the neuroendocrine regulation of the motivation to engage in ingestive behavior.

Effects of methylphenidate on appetite and growth in children diagnosed with attention deficit and hyperactivity disorder

“…Pancreas and fatty tissue appear to be influential among the mechanisms that regulate appetite, the central nervous system, the gastrointestinal system (GIS), several anorexigenic and orexigenic peptides, and hormonal mediators released from the adrenals (1)(2)(3)(4)(5). Particular emphasis is being put on the leptin and ghrelin system in the pathophysiology of many diseases that affect appetite (6)(7)(8)(9)(10)(11).…”

Diagnostic Biomarkers for Posttraumatic Stress Disorder: Promising Horizons from Translational Neuroscience Research

“…Neuropeptide Y (NPY) is an orexigenic peptide neurotransmitter (58) that also shows anxiolytic properties via antagonism of CRH and noradrenergic systems (59). Trauma exposure (60) and PTSD (59) are associated with attenuated peripheral levels of NPY and, conversely, resilience to trauma is associated with increased NPY levels (61).…”

“…Trauma exposure (60) and PTSD (59) are associated with attenuated peripheral levels of NPY and, conversely, resilience to trauma is associated with increased NPY levels (61). Ghrelin, an orexigenic peptide secreted from the stomach (58), displays fear-enhancing effects in rodents (62) and could serve as a biomarker of trauma exposure and PTSD. More recently, individuals with PTSD have shown a hyperinsulinemic response to an oral glucose challenge (63).…”

Are Environmental Contaminants Responsible for ‘Globesity’?

“…Hormones such as leptin and insulin help to regulate dopamine production [26]. There is evidence that increased leptin signaling specifically in the ventral tegmental area (VTA) decreases food intake and firing rates of DA neurons, while treatments that impair leptin signaling in the VTA increase DA neuronal firing rates, food intake, and the proclivity to ingest highly palatable foods [for review 27]. In healthy people, neurotransmitters work together in a pattern of stimulation or inhibition, the effects spreading downward like a cascade from stimulus input to complex patterns of response leading to feelings of well-being [28].…”