Elucidation of the anatomy of a satiety network: Focus on connectivity of the parabrachial nucleus in the adult rat |
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| Authors: | Györgyi Zséli Barbara Vida Anais Martinez Ronald M. Lechan Arshad M. Khan Csaba Fekete |
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| Affiliation: | 1. Department of Endocrine Neurobiology, Institute of Experimental Medicine, Hungarian Academy of Sciences, Budapest, Hungary;2. Neuroendocrinology Program, Semmelweis University Neurosciences Doctoral School, Budapest, Hungary;3. Department of Neuroscience, Faculty of Information Technology, Pázmány Péter Catholic University, Budapest, Hungary;4. UTEP Systems Neuroscience Laboratory, Department of Biological Sciences and Border Biomedical Research Center, University of Texas at El Paso, El Paso, Texas;5. Graduate Program in Pathobiology, Department of Biological Sciences, University of Texas at El Paso, El Paso, Texas;6. Department of Medicine, Division of Endocrinology, Diabetes and Metabolism, Tupper Research Institute, Tufts Medical Center, Boston, Massachusetts;7. Department of Neuroscience, Tufts University School of Medicine, Boston, Massachusetts |
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| Abstract: | We hypothesized that brain regions showing neuronal activation after refeeding comprise major nodes in a satiety network, and tested this hypothesis with two sets of experiments. Detailed c‐Fos mapping comparing fasted and refed rats was performed to identify candidate nodes of the satiety network. In addition to well‐known feeding‐related brain regions such as the arcuate, dorsomedial, and paraventricular hypothalamic nuclei, lateral hypothalamic area, parabrachial nucleus (PB), nucleus of the solitary tract and central amygdalar nucleus, other refeeding activated regions were also identified, such as the parastrial and parasubthalamic nuclei. To begin to understand the connectivity of the satiety network, the interconnectivity of PB with other refeeding‐activated neuronal groups was studied following administration of anterograde or retrograde tracers into the PB. After allowing for tracer transport time, the animals were fasted and then refed before sacrifice. Refeeding‐activated neurons that project to the PB were found in the agranular insular area; bed nuclei of terminal stria; anterior hypothalamic area; arcuate, paraventricular, and dorsomedial hypothalamic nuclei; lateral hypothalamic area; parasubthalamic nucleus; central amygdalar nucleus; area postrema; and nucleus of the solitary tract. Axons originating from the PB were observed to closely associate with refeeding‐activated neurons in the agranular insular area; bed nuclei of terminal stria; anterior hypothalamus; paraventricular, arcuate, and dorsomedial hypothalamic nuclei; lateral hypothalamic area; central amygdalar nucleus; parasubthalamic nucleus; ventral posterior thalamic nucleus; area postrema; and nucleus of the solitary tract. These data indicate that the PB has bidirectional connections with most refeeding‐activated neuronal groups, suggesting that short‐loop feedback circuits exist in this satiety network. J. Comp. Neurol. 524:2803–2827, 2016. © 2016 Wiley Periodicals, Inc. |
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| Keywords: | refeeding parabrachial nucleus anterograde tract tracing retrograde tract tracing c‐Fos |
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