Paola Binda1, Roy Eldor2, Claudia Huerta3, John Adams4, John Lancaster3, Peter Fox3, Stefano Del Prato5, Ralph DeFronzo4, Muhammad Abdul-Ghani4,6, Giuseppe Daniele4,5. 1. Department of Translational Research on New Technologies in Medicine and Surgery, University of Pisa, Pisa, Italy. 2. Diabetes Unit-Institute of Endocrinology, Metabolism & Hypertension at The Tel Aviv Sourasky Medical Center, Tel-Aviv, Israel. 3. Imaging Research Center, University of Texas Health Science Center at San Antonio, San Antonio, TX, USA. 4. Division of Diabetes, University of Texas Health Science Center at San Antonio, San Antonio, TX, USA. 5. Department of Clinical and Experimental Medicine, Section of Diabetes, University of Pisa, Pisa, Italy. 6. Diabetes and Obesity Clinical Research Center, Hamad General Hospital, Doha, Qatar.
Abstract
BACKGROUND: Increasing evidence suggests that metabolism affects brain physiology. Here, we examine the effect of GLP-1 on simple visual-evoked functional Magnetic Resonance Imaging (fMRI) responses in cortical areas. METHODS: Lean (n = 10) and nondiabetic obese (n = 10) subjects received exenatide (a GLP-1 agonist) or saline infusion, and fMRI responses to visual stimuli (food and nonfood images) were recorded. We analysed the effect of exenatide on fMRI signals across the cortical surface with special reference to the visual areas. We evaluated the effects of exenatide on the raw fMRI signal and on the fMRI signal change during visual stimulation (vs rest). RESULTS: In line with previous studies, we find that exenatide eliminates the preference for food (over nonfood) images present under saline infusion in high-level visual cortex (temporal pole). In addition, we find that exenatide (vs saline) also modulates the response of early visual areas, enhancing responses to both food and nonfood images in several extrastriate occipital areas, similarly in obese and lean participants. Unexpectedly, exenatide increased fMRI raw signals (signal intensity during rest periods without stimulation) in a large occipital region, which were negatively correlated to BMI. CONCLUSIONS: In both lean and obese individuals, exenatide affects neural processing in visual cortex, both in early visual areas and in higher order areas. This effect may contribute to the known effect of GLP1 analogues on food-related behaviour.
BACKGROUND: Increasing evidence suggests that metabolism affects brain physiology. Here, we examine the effect of GLP-1 on simple visual-evoked functional Magnetic Resonance Imaging (fMRI) responses in cortical areas. METHODS: Lean (n = 10) and nondiabetic obese (n = 10) subjects received exenatide (a GLP-1 agonist) or saline infusion, and fMRI responses to visual stimuli (food and nonfood images) were recorded. We analysed the effect of exenatide on fMRI signals across the cortical surface with special reference to the visual areas. We evaluated the effects of exenatide on the raw fMRI signal and on the fMRI signal change during visual stimulation (vs rest). RESULTS: In line with previous studies, we find that exenatide eliminates the preference for food (over nonfood) images present under saline infusion in high-level visual cortex (temporal pole). In addition, we find that exenatide (vs saline) also modulates the response of early visual areas, enhancing responses to both food and nonfood images in several extrastriate occipital areas, similarly in obese and lean participants. Unexpectedly, exenatide increased fMRI raw signals (signal intensity during rest periods without stimulation) in a large occipital region, which were negatively correlated to BMI. CONCLUSIONS: In both lean and obese individuals, exenatide affects neural processing in visual cortex, both in early visual areas and in higher order areas. This effect may contribute to the known effect of GLP1 analogues on food-related behaviour.
Authors: Gregory G Brown; Lisa T Eyler Zorrilla; Bassem Georgy; Sandra S Kindermann; Eric C Wong; Richard B Buxton Journal: J Cereb Blood Flow Metab Date: 2003-07 Impact factor: 6.200
Authors: Sherry L Pagoto; Kristin L Schneider; Jamie S Bodenlos; Bradley M Appelhans; Matthew C Whited; Yunsheng Ma; Stephenie C Lemon Journal: Obesity (Silver Spring) Date: 2011-10-20 Impact factor: 5.002
Authors: Astrid Wallner; Alexandra Hirz; Edith Schober; Harald Harbich; Thomas Waldhoer Journal: Wien Klin Wochenschr Date: 2010-03 Impact factor: 1.704
Authors: Marc-Andre Cornier; Andrea K Salzberg; Dawnielle C Endly; Daniel H Bessesen; Donald C Rojas; Jason R Tregellas Journal: PLoS One Date: 2009-07-28 Impact factor: 3.240