title: Transgenic labeling of higher order neuronal circuits linked to phospholipase C-β2-expressing taste bud cells in medaka fish.
abstract: The sense of taste plays a pivotal role in the food-selecting behaviors of vertebrates. We have shown that the fish ortholog of the phospholipase C gene (plc-β2) is expressed in a subpopulation of taste bud cells that transmit taste stimuli to the central nervous system to evoke favorable and aversive behaviors. We generated transgenic medaka expressing wheat germ agglutinin (WGA) under the control of a regulatory region of the medaka plc-β2 gene to analyze the neuronal circuit connected to these sensory cells. Immunohistochemical analysis of the transgenic fish 12 days post fertilization revealed that the WGA protein was transferred to cranial sensory ganglia and several nuclei in the hindbrain. WGA signals were also detected in the secondary gustatory nucleus in the hindbrain of 3-month-old transgenic fish. WGA signals were observed in several diencephalic and telencephalic regions in 9-month-old transgenic fish. The age-dependent increase in the labeled brain regions strongly suggests that labeling occurred at taste bud cells and progressively extended to cranial nerves and neurons in the central nervous system. These data are the first to demonstrate the tracing of higher order gustatory neuronal circuitry that is associated with a specific subpopulation of taste bud cells. These results provide insight into the basic neuronal architecture of gustatory information processing that is common among vertebrates.
authors.affiliation: Department of Applied Biological Chemistry, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo, 113-8657, Japan.
authors.forename: Takashi
authors.initials: T
authors.lastname: Ieki
authors.forename: Shinji
authors.initials: S
authors.lastname: Okada
authors.forename: Yoshiko
authors.initials: Y
authors.lastname: Aihara
authors.forename: Makoto
authors.initials: M
authors.lastname: Ohmoto
authors.forename: Keiko
authors.initials: K
authors.lastname: Abe
authors.forename: Akihito
authors.initials: A
authors.lastname: Yasuoka
authors.forename: Takumi
authors.initials: T
authors.lastname: Misaka
mesh_terms: D000367:Age Factors; D000818:Animals; D030801:Animals, Genetically Modified; D005260:Female; D018507:Gene Expression Regulation, Developmental / Q000235:genetics; D007814:Larva; D008297:Male; D009415:Nerve Net / Q000378:metabolism*; D009474:Neurons / Q000145:classification / Q000378:metabolism*; D009990:Oryzias / Q000033:anatomy & histology*; D054799:Phospholipase C beta / Q000235:genetics* / Q000378:metabolism*; D013650:Taste Buds / Q000166:cytology*; D014909:Wheat Germ Agglutinins / Q000235:genetics / Q000378:metabolism
chemical_list: D014909:Wheat Germ Agglutinins; D054799:Phospholipase C beta