Expression of vesicular glutamate transporters type 1 and 2 in sensory and autonomic neurons innervating the mouse colorectum

• Published in: Journal of comparative neurology (1911) 2011-11, Vol.519 (16), p.3346-3366
• Main Authors: Brumovsky, Pablo R., Robinson, David R., La, Jun-Ho, Seroogy, Kim B., Lundgren, Kerstin H., Albers, Kathryn M., Kiyatkin, Michael E., Seal, Rebecca P., Edwards, Robert H., Watanabe, Masahiko, Hökfelt, Tomas, Gebhart, G.F.
• Format: Article
• Language: English
• Subjects: Animals; Antibodies; Autonomic nervous system; Calcitonin gene-related peptide; colon; Colon - innervation; Colon - metabolism; Data processing; Dorsal root ganglia; DRG; Enteric nervous system; Fibers; Ganglia, Spinal - metabolism; glutamate; Glutamic acid transporter; Immunohistochemistry; In Situ Hybridization; Male; Medicin och hälsovetenskap; Mice; Mice, Inbred BALB C; Motility; mRNA; myenteric plexus; Myenteric Plexus - metabolism; Nerves; Neurons; neuropeptides; Neurotransmission; pain; pelvic nerve; Pelvis; Probes; Rectum - innervation; Rectum - metabolism; Sensory neurons; Sensory Receptor Cells - metabolism; Subpopulations; Vesicular Glutamate Transport Protein 1 - biosynthesis; Vesicular Glutamate Transport Protein 2 - biosynthesis
• ISSN: 0021-9967; 1096-9861; 1096-9861
• DOI: 10.1002/cne.22730

Vesicular glutamate transporters (VGLUTs) have been extensively studied in various neuronal systems, but their expression in visceral sensory and autonomic neurons remains to be analyzed in detail. Here we studied VGLUTs type 1 and 2 (VGLUT1 and VGLUT2, respectively) in neurons innervating the mouse colorectum. Lumbosacral and thoracolumbar dorsal root ganglion (DRG), lumbar sympathetic chain (LSC), and major pelvic ganglion (MPG) neurons innervating the colorectum of BALB/C mice were retrogradely traced with Fast Blue, dissected, and processed for immunohistochemistry. Tissue from additional naïve mice was included. Previously characterized antibodies against VGLUT1, VGLUT2, and calcitonin gene‐related peptide (CGRP) were used. Riboprobe in situ hybridization, using probes against VGLUT1 and VGLUT2, was also performed. Most colorectal DRG neurons expressed VGLUT2 and often colocalized with CGRP. A smaller percentage of neurons expressed VGLUT1. VGLUT2‐immunoreactive (IR) neurons in the MPG were rare. Abundant VGLUT2‐IR nerves were detected in all layers of the colorectum; VGLUT1‐IR nerves were sparse. A subpopulation of myenteric plexus neurons expressed VGLUT2 protein and mRNA, but VGLUT1 mRNA was undetectable. In conclusion, we show 1) that most colorectal DRG neurons express VGLUT2, and to a lesser extent, VGLUT1; 2) abundance of VGLUT2‐IR fibers innervating colorectum; and 3) a subpopulation of myenteric plexus neurons expressing VGLUT2. Altogether, our data suggests a role for VGLUT2 in colorectal glutamatergic neurotransmission, potentially influencing colorectal sensitivity and motility. J. Comp. Neurol. 519:3346–3366, 2011. © 2011 Wiley‐Liss, Inc.