Journal of Neuroscience, Vol 7, 3561-3565, Copyright © 1987 by Society for Neuroscience
Dye-coupling in taste buds in the mudpuppy, Necturus maculosus
J Yang and SD Roper
Department of Anatomy and Neurobiology, Colorado State University, Fort Collins 80523.
Electrical coupling in taste buds and in non-taste lingual epithelium in
the mudpuppy was examined by injecting cells with a fluorescent dye,
Lucifer yellow. Lucifer yellow coupling has been shown to indicate the
presence of electrical junctions between cells. Lucifer yellow-filled taste
cells usually have an elongate shape. Cells were an average of 111 microns
long and were 13 microns in diameter at the widest region (nucleus). In
taste buds, from a sample of 105 impalements we detected Lucifer yellow
coupling in 21 cases: dye-coupled pairs of cells were observed in 17 cases,
and trios of cells in 4 cases. Larger subsets of coupled cells (greater
than 3) were not observed. Dye-coupled cells were usually equally intensely
stained. In non-taste epithelium, we examined dye-coupling in the
superficial and basal layers. Extensive Lucifer yellow coupling was found
in the basal layer (15/15 cases). The number of cells coupled to the
dye-injected cell varied from 3 to 5. In the superficial epithelium,
dye-coupling was rare (1/45 cases). No dye- coupling was observed between
epithelial cells and taste cells at the taste pore region. We conclude that
strong electrical coupling in groups of 2-3 cells occurs in the mudpuppy
taste buds. Coupling may occur selectively between identical types of taste
cells (dark, light, etc.), but this remains to be determined. Electrical
coupling also exists among basal epithelial cells but not in the
superficial epithelial layers.