title: Diet-induced obesity resistance of Kv1.3-/- mice is olfactory bulb dependent.
abstract: Gene-targeted deletion of the voltage-gated potassium channel, Kv1.3 (Kv1.3-/-), increases olfactory sensitivity and discriminatory ability, and causes resistance to diet-induced obesity (DIO) in mice. The present study aimed to determine whether the enhanced olfactory ability of the Kv1.3-/- mouse contributes to the resistance to DIO. Kv1.3+/+ and Kv1.3-/- mice were subject to bilateral olfactory bulbectomy (OBX) or sham surgery at 9 weeks of age and placed on either a control chow diet or a 32% moderately high-fat diet (MHF). Caloric and water intake, locomotor activity and oxygen consumption were monitored after 5 weeks of diet treatment. At the end of 26 weeks of diet treatment, fat pad weight and blood chemistry were evaluated. Kv1.3+/+ mice exhibited a significant increase in weight, adiposity, fasting glucose and fasting leptin in response to the MHF-diet, with or without OBX. When treated with a MHF-diet, Kv1.3-/- mice gained significantly less weight than Kv1.3+/+ mice and exhibited a significant increase in light phase metabolism. OBX of Kv1.3-/- mice prevented the resistance to DIO and concomitant up-regulation of light phase metabolism at the same time as decreasing dark phase metabolism and total energy expenditure. These findings suggest that pathways activated in Kv1.3-/- that increased energy expenditure and led to resistance to DIO are olfactory bulb dependent. Thus, these findings add to a growing body of evidence suggesting that the olfactory system can modulate the pathways involved in the regulation of energy balance.
authors.affiliation: Program in Neuroscience, The Florida State University, Tallahassee, FL, USA. krt21@pitt.edu
authors.forename: K
authors.initials: K
authors.lastname: Tucker
authors.forename: J M
authors.initials: JM
authors.lastname: Overton
authors.forename: D A
authors.initials: DA
authors.lastname: Fadool
mesh_terms: D000818:Animals; D001522:Behavior, Animal; D002153:Calorimetry, Indirect; D004032:Diet; D002149:Energy Intake; D018390:Gene Targeting; D051664:Kv1.3 Potassium Channel / Q000235:genetics / Q000502:physiology*; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D009765:Obesity / Q000235:genetics / Q000503:physiopathology* / Q000517:prevention & control; D009830:Olfactory Bulb / Q000503:physiopathology* / Q000601:surgery
chemical_list: D051664:Kv1.3 Potassium Channel