Olfactory bulbectomy increases food intake and hypothalamic neuropeptide Y in obesity-prone but not obesity-resistant rats

• Published in: Behavioural brain research 2007-06, Vol.180 (2), p.190-196
• Main Authors: Primeaux, Stefany D., Barnes, Maria J., Bray, George A.
• Format: Article
• Language: English
• Subjects: Adult and adolescent clinical studies; Amygdala; Animals; Behavioral psychophysiology; Biological and medical sciences; Body Weight - physiology; Depression; Disease Models, Animal; Eating - physiology; Exploratory Behavior - physiology; Food intake; Fundamental and applied biological sciences. Psychology; Hypothalamus; Hypothalamus - metabolism; Male; Medical sciences; Metabolic diseases; Mood disorders; Neuropeptide Y; Neuropeptide Y - genetics; Neuropeptide Y - metabolism; Obesity; Obesity - genetics; Obesity - pathology; Obesity - physiopathology; Obesity-prone; Olfactory Bulb - physiology; Olfactory Bulb - surgery; Olfactory bulbectomy; Psychology. Psychoanalysis. Psychiatry; Psychology. Psychophysiology; Psychopathology. Psychiatry; Rats; Rats, Inbred Strains; Receptors, Neuropeptide Y - genetics; Receptors, Neuropeptide Y - metabolism; Reverse Transcriptase Polymerase Chain Reaction - methods; RNA, Messenger - biosynthesis; Time Factors
• ISSN: 0166-4328; 1872-7549
• DOI: 10.1016/j.bbr.2007.03.005

Obese individuals often suffer from depression. The olfactory bulbectomy (OBX) model is an animal model of depression that produces behavioral, physiological, and neurochemical alterations resembling clinical depression. The OBX model was employed to assess depression-related changes in food intake in obesity-prone, Osborne–Mendel (OM) rats and obesity-resistant, S5B/Pl rats. OBX increased food intake in OM rats beginning 7 days following surgery, however, OBX did not alter food intake in S5B/Pl rats at any time point. Fourteen days following surgery, OBX significantly increased locomotor activity (total lines crossed and rears) in the openfield test in OM and S5B/Pl rats. Fifteen days following surgery, prepro-neuropeptide Y (NPY) mRNA levels were significantly increased in the hypothalamus of bulbectomized OM rats and in the medial nucleus of the amygdala of bulbectomized OM and S5B/Pl rats. OBX decreased NPY Y2 receptor mRNA levels in the hypothalamus and medial nucleus of the amygdala in OM rats, while increasing NPY Y2 receptor mRNA levels in the medial nucleus of the amygdala of S5B/Pl rats. These data indicate that though both obesity-prone and obesity-resistant strains were susceptible to the locomotor effects of OBX, food intake and hypothalamic prepro-NPY mRNA were only increased in OM rats. Therefore, strain specific alterations in hypothalamic NPY may account for increased food intake in the obesity-prone rats following OBX, and suggests a potential mechanism to explain the comorbidity of obesity and depression.