The molecular events underlying chemical transduction in lingual epithelia are not well understood. In this proposal we will measure the electrical, chemical and structural changes that occur in mammalian lingual epithelia in response to chemical stimuli so that models of taste transduction can be tested or formulated as the evidence dictates. The recent discovery that the tongue actively transports ions (1) suggests that previous models of taste transduction that have assumed it to be impermeable to ions and that there are separate pathways for Na+, K+, and H+, and non-electrolytes may have to be modified. Here the active and passive transport properties of dog tongue will be studied by mounting it in a Ussing chamber. The role of taste cells and their proposed receptors in the transduction process will be studied by comparing the passive and active transport behavior of the tongue in the presence and absence of taste papillae. Morphological and intracellular ion changes will be measured using both conventional electron microscopy and electron probe microanalysis. These data will then be used to formulate mechanisms of taste transduction for salts, acids, D and L amino acids, and saccharides. In major goal of this research is to describe the dog tongue as a transporting epithelium. The transport pathways for mono and divalent anions and cations, saccharides, acids, and amino acids will be determined as well as their selectivity isotherms. The effect of ADH, copper, D-penicillamine, nystatin, amiloride, ouabain, C-AMP, intracellular Ca++, and site-specific reagents known to eliminate specific taste responses will be tested for the purpose of determining rate-limiting steps of transport, eliminating particular transport pathways, to determine those cell types that respond to various chemical stimuli, and to determine the role of various hormones in the transduction process. The data we obtained on the voltaged clamped preparation will be correlated with taste perception data which to date have been in substantial agreement. This voltage-clamped epithelial preparation can be used to assay the effect of drugs used to treat patients with taste disorders (such as hypogeusia, which arise at low copper concentrations) and also as a bioassay to identify new artificial tastants.

Agency
National Institute of Health (NIH)
Institute
National Institute of Neurological Disorders and Stroke (NINDS)
Type
Research Project (R01)
Project #
5R01NS020669-02
Application #
3401190
Study Section
Communication Sciences and Disorders (CMS)
Project Start
1984-12-01
Project End
1987-11-30
Budget Start
1985-12-01
Budget End
1986-11-30
Support Year
2
Fiscal Year
1986
Total Cost
Indirect Cost
Name
Duke University
Department
Type
Schools of Medicine
DUNS #
071723621
City
Durham
State
NC
Country
United States
Zip Code
27705
Liu, L; Pugh, W; Ma, H et al. (1993) Identification of acetylcholine receptors in adult rat trigeminal ganglion neurons. Brain Res 617:37-42
Fralix, T A; Ceckler, T L; Wolff, S D et al. (1991) Lipid bilayer and water proton magnetization transfer: effect of cholesterol. Magn Reson Med 18:214-23
Sostman, A L; Simon, S A (1991) Trigeminal nerve responses in the rat elicited by chemical stimulation of the tongue. Arch Oral Biol 36:95-102
Elliott, E J; Simon, S A (1990) The anion in salt taste: a possible role for paracellular pathways. Brain Res 535:9-17
Holland, V F; Zampighi, G A; Simon, S A (1989) Morphology of fungiform papillae in canine lingual epithelium: location of intercellular junctions in the epithelium. J Comp Neurol 279:13-27
Simon, S A; Labarca, P; Robb, R (1989) Activation by saccharides of a cation-selective pathway on canine lingual epithelium. Am J Physiol 256:R394-402
Zampighi, G A; Hall, J E; Ehring, G R et al. (1989) The structural organization and protein composition of lens fiber junctions. J Cell Biol 108:2255-75
Zampighi, G; Kreman, M; Ramon, F et al. (1988) Structural characteristics of gap junctions. I. Channel number in coupled and uncoupled conditions. J Cell Biol 106:1667-78
Simon, S A; Robb, R; Schiffman, S S (1988) Transport pathways in rat lingual epithelium. Pharmacol Biochem Behav 29:257-67
Garvin, J L; Robb, R; Simon, S A (1988) Spatial map of salts and saccharides on dog tongue. Am J Physiol 255:R117-22

Showing the most recent 10 out of 15 publications