Hypothalamic and hindbrain NPY, AGRP and NE increase consummatory feeding responses

• Published in: Physiology & behavior Vol. 90; no. 5; pp. 744 - 750
• Main Authors: Taylor, Kelli, Lester, Erin, Hudson, Bryan, Ritter, Sue
• Format: Journal Article
• Language: English
• Published: Cambridge Elsevier Inc 23.04.2007; New York, NY Elsevier
• Subjects: Administration, Oral; Agouti-Related Protein; Analysis of Variance; Animals; Appetite Regulation - physiology; Appetitive Behavior - physiology; Appetitive feeding behavior; Behavioral psychophysiology; Biological and medical sciences; Consummatory feeding responses; Eating - physiology; Food intake; Fourth ventricle; Fundamental and applied biological sciences. Psychology; Hindbrain; Hypothalamus - metabolism; Injections, Intraventricular; Intercellular Signaling Peptides and Proteins - administration & dosage; Intercellular Signaling Peptides and Proteins - physiology; Male; Microinjections; Neuropeptide Y; Neuropeptide Y - administration & dosage; Neuropeptide Y - physiology; Norepinephrine; Norepinephrine - administration & dosage; Norepinephrine - physiology; Paraventricular nucleus of the hypothalamus; Psychiatry; Psychology. Psychoanalysis. Psychiatry; Psychology. Psychophysiology; Rats; Rats, Sprague-Dawley; Rhombencephalon - metabolism; Neuropeptide Y; Fourth ventricle; Paraventricular nucleus of the hypothalamus; Agouti-related protein; Food intake; Appetitive feeding behavior; Hindbrain; Norepinephrine; Consummatory feeding responses; Feeding behavior; AGOUTI related protein; Central nervous system; Hypothalamus; Paraventricular nucleus; Catecholamine; Encephalon; Feeding; Neurotransmitter
• ISSN: 0031-9384; 1873-507X
• DOI: 10.1016/j.physbeh.2006.12.014

Abstract Feeding behavior is comprised of both appetitive and consummatory responses to food. Appetitive responses include the motivated acquisition of food. Consummatory responses, including swallowing, are those that move the food from the mouth to the stomach. Intraoral delivery of liquid food bypasses the requirement for appetitive responses and has been used to examine consummatory responses directly in intact rats. In the present study, we administered neuropeptide Y (NPY), agouti-related protein (AGRP) and norepinephrine (NE), into the paraventricular nucleus of the hypothalamus (PVN) or into the fourth cerebral ventricle to examine their effects on the consummatory component of feeding behavior in the rat. To measure consummatory responses, milk (40% lactose free cow's milk diluted with water) was infused intraorally through a chronic cheek fistula (1 ml/min), using an alternating 5 min on − 1 min off schedule, until rejection occurred. We found that both hypothalamic and fourth ventricle injections of NPY, AGRP and NE significantly increased consumption of the intraorally-delivered milk. Our results indicate that the circuitry for modulation of consummatory ingestive responses includes NE, NPY and AGRP receptors operating in both hypothalamic and hindbrain sites.