Electrophysiological characterization of voltage-gated currents in defined taste cell types of mice.
Despite extensive immunological characterization of the cells within taste buds, little is known about the functional significance of the different cell types. In this study, we use taste cells isolated from mouse vallate and foliate papillae to characterize voltage-gated currents in the three principal elongate types of taste cells: type I, II, and III. Cell types are identified by using antibodies to external epitopes [antigen H for type I cells, antigen A for type II cells, and neural cell adhesion molecule (NCAM) for type III cells]. In addition, we identify the subset of type II cells that contains alpha-gustducin, a G-protein involved in bitter transduction, by using transgenic mice expressing green fluorescent protein under the control of the gustducin promoter. Our results indicate that antigen H-immunoreactive (-IR) cells and many of the antigen A-IR cells have small voltage-gated inward Na(+) and outward K(+) currents but no voltage-gated Ca(2+) currents. In contrast, a subset of antigen A-IR cells and all NCAM-IR cells have large inward Na(+) and outward K(+) currents as well as voltage-gated Ca(2+) currents. Unexpectedly, all gustducin-expressing cells lacked voltage-gated Ca(2+) currents, suggesting that these cells use mechanisms other than classical synapses to communicate signals to the brain.
Medler
Kathryn F
KF
Department of Biomedical Sciences, Colorado State University, Fort Collins, Colorado 80523, USA. Kathryn.Medler@colostate.edu
Margolskee
Robert F
RF
Kinnamon
Sue C
SC
D000017:ABO Blood-Group System / Q000032:analysis; D000818:Animals; D002478:Cells, Cultured; D004553:Electric Conductivity; D049452:Green Fluorescent Proteins; D015640:Ion Channel Gating; D008164:Luminescent Proteins / Q000032:analysis / Q000235:genetics; D051379:Mice; D019006:Neural Cell Adhesion Molecules / Q000032:analysis; D018408:Patch-Clamp Techniques; D013650:Taste Buds / Q000737:chemistry / Q000166:cytology* / Q000502:physiology*; D015293:Transducin / Q000235:genetics
D000017:ABO Blood-Group System; D008164:Luminescent Proteins; D019006:Neural Cell Adhesion Molecules; D049452:Green Fluorescent Proteins; C075192:gustducin; D015293:Transducin