title: Information processing in brainstem bitter taste-relaying neurons defined by genetic tracing.
abstract: Bitter reception is mediated by taste receptor cells that coexpress multiple T2Rs, a family of G-protein-coupled receptors. However, it remains elusive how bitter taste information is translated in the brain into appropriate behavioral responses. Here we used a combination of genetic tracing and electrophysiological and immunohistochemical analyses in mice to functionally characterize the neurons in the solitary tract nuclei of the medulla, which receive input from mT2R5-expressing cells. The neurons defined by a transneuronal tracer originating from mT2R5-expressing cells receive glutamatergic synaptic input via the AMPA receptor. The satiety peptide cholecystokinin increases glutamatergic transmission, suggesting an interaction between information processing of taste and the homeostatic control of feeding. Nevertheless, the tracer-labeled neuron types are heterogeneous, and can be classified into catecholamine and pro-opiomelanocortin neurons. Our data reveal that the architectural solution in the first-order central relay that processes information from mT2R5-expressing cells uses unique ensembles of neurons with different neurotransmitters.
authors.affiliation: Department of Physiology and Oral Physiology, Institute of Biomedical & Health Sciences, Hiroshima University, Kasumi 1-2-3, Minami-ku, Hiroshima 734-8553, Japan. Electronic address: sugisan@hiroshima-u.ac.jp.
authors.forename: M
authors.initials: M
authors.lastname: Sugita
authors.forename: K
authors.initials: K
authors.lastname: Yamamoto
authors.forename: C
authors.initials: C
authors.lastname: Hirono
authors.forename: Y
authors.initials: Y
authors.lastname: Shiba
mesh_terms: D000818:Animals; D001933:Brain Stem / Q000502:physiology*; D002395:Catecholamines / Q000378:metabolism; D051766:Early Growth Response Protein 1 / Q000096:biosynthesis / Q000235:genetics; D055724:Electrophysiological Phenomena / Q000502:physiology; D049452:Green Fluorescent Proteins; D006706:Homeostasis / Q000502:physiology; D007150:Immunohistochemistry; D051379:Mice; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D008856:Microscopy, Fluorescence; D018408:Patch-Clamp Techniques; D016133:Polymerase Chain Reaction; D011333:Pro-Opiomelanocortin / Q000378:metabolism; D043562:Receptors, G-Protein-Coupled / Q000502:physiology; D011984:Sensory Receptor Cells / Q000502:physiology*; D017552:Solitary Nucleus / Q000502:physiology; D013649:Taste / Q000502:physiology*
chemical_list: D002395:Catecholamines; D051766:Early Growth Response Protein 1; C486109:Egr1 protein, mouse; D043562:Receptors, G-Protein-Coupled; D049452:Green Fluorescent Proteins; D011333:Pro-Opiomelanocortin
keywords: 4-(2-hydroxyethyl)-1-piperazineethanesulfonic acid; AITC; BSA; CCK; CSF; DIC; EGFP; EGTA; EPSC; GFP; GLP-1; HEPES; LiCl; NTS; PBN; PBS; POMC; RF; TH; allyl isothiocyanate; alpha-melanocyte-stimulating hormone; bitter taste; bovine serum albumin; catecholamine neuron; cerebral spinal fluid; cholecystokinin; differential interference contrast; enhanced green fluorescent protein; ethylene glycol tetraacetic acid; excitatory postsynaptic currents; glucagon-like peptide 1; green fluorescent protein; lithium chloride; nucleus of the solitary tract; parabrachial nuclei; phosphate-buffered saline; pro-opiomelanocortin; reticular formation; the solitary tract nuclei; tyrosine hydroxylase; α-MSH