caa a22 4500 606203087 CHVBK 20210128100956.0 cr unu---uuuuu 210128e20150901xx s 000 0 eng 10.1007/s00429-014-0841-6 doi (NATIONALLICENCE)springer-10.1007/s00429-014-0841-6 Glutamatergic phenotype of glucagon-like peptide 1 neurons in the caudal nucleus of the solitary tract in rats [Elektronische Daten] [H. Zheng, R. Stornetta, K. Agassandian, Linda Rinaman] The expression of a vesicular glutamate transporter (VGLUT) suffices to assign a glutamatergic phenotype to neurons and other secretory cells. For example, intestinal L cells express VGLUT2 and secrete glutamate along with glucagon-like peptide 1 (GLP1). We hypothesized that GLP1-positive neurons within the caudal (visceral) nucleus of the solitary tract (cNST) also are glutamatergic. To test this, the axonal projections of GLP1 and other neurons within the cNST were labeled in rats via iontophoretic delivery of anterograde tracer. Dual immunofluorescence and confocal microscopy was used to visualize tracer-, GLP1-, and VGLUT2-positive fibers within brainstem, hypothalamic, and limbic forebrain nuclei that receive input from the cNST. Electron microscopy was used to confirm GLP1 and VGLUT2 immunolabeling within the same axon varicosities, and fluorescent in situ hybridization was used to examine VGLUT2 mRNA expression by GLP1-positive neurons. Most anterograde tracer-labeled fibers displayed VGLUT2-positive varicosities, providing new evidence that ascending axonal projections from the cNST are primarily glutamatergic. Virtually all GLP1-positive varicosities also were VGLUT2-positive. Electron microscopy confirmed the colocalization of GLP1 and VGLUT2 immunolabeling in axon terminals that formed asymmetric (excitatory-type) synapses with unlabeled dendrites in the hypothalamus. Finally, in situ hybridization confirmed that GLP1-positive cNST neurons express VGLUT2 mRNA. Thus, hindbrain GLP1 neurons in rats are equipped to store glutamate in synaptic vesicles, and likely co-release both glutamate and GLP1 from axon varicosities and terminals in the hypothalamus and other brain regions. Springer-Verlag Berlin Heidelberg, 2014 Glutamate nationallicence VGLUT2 nationallicence Paraventricular nucleus of the hypothalamus nationallicence Bed nucleus of the stria terminals nationallicence Electron microscopy nationallicence In situ hybridization nationallicence Confocal microscopy nationallicence Zheng H. Department of Neuroscience, University of Pittsburgh, A210 Langley Hall, 15260, Pittsburgh, PA, USA aut Stornetta R. Department of Pharmacology, University of Virginia, Charlottesville, VA, USA aut Agassandian K. Department of Neuroscience, University of Pittsburgh, A210 Langley Hall, 15260, Pittsburgh, PA, USA aut Rinaman Linda Department of Neuroscience, University of Pittsburgh, A210 Langley Hall, 15260, Pittsburgh, PA, USA aut Brain Structure and Function Springer Berlin Heidelberg 220/5(2015-09-01), 3011-3022 1863-2653 220:5<3011 2015 220 429 https://doi.org/10.1007/s00429-014-0841-6 text/html Onlinezugriff via DOI BK010053 XK010053 XK010000 Metadata rights reserved Springer special CC-BY-NC licence nationallicence 1 research-article jats NATIONALLICENCE NATIONALLICENCE NL-springer NATIONALLICENCE 856 40 https://doi.org/10.1007/s00429-014-0841-6 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Zheng H. Department of Neuroscience, University of Pittsburgh, A210 Langley Hall, 15260, Pittsburgh, PA, USA aut NATIONALLICENCE 700 1- Stornetta R. Department of Pharmacology, University of Virginia, Charlottesville, VA, USA aut NATIONALLICENCE 700 1- Agassandian K. Department of Neuroscience, University of Pittsburgh, A210 Langley Hall, 15260, Pittsburgh, PA, USA aut NATIONALLICENCE 700 1- Rinaman Linda Department of Neuroscience, University of Pittsburgh, A210 Langley Hall, 15260, Pittsburgh, PA, USA aut NATIONALLICENCE 773 0- Brain Structure and Function Springer Berlin Heidelberg 220/5(2015-09-01), 3011-3022 1863-2653 220:5<3011 2015 220 429