AJP - Regulatory, Integrative and Comparative Physiology, Vol 251, Issue 3 598-R608, Copyright © 1986 by American Physiological Society
Epithelial responses of rabbit tongues and their involvement in taste transduction
S. A. Simon, R. Robb and J. L. Garvin
The response of rabbit tongue, placed in a modified Ussing chamber, to
salts [KCl, NaCl, NH4Cl, tetraethylammonium chloride (TEACl)], sweeteners
(D-glucose, sucrose), acid (HCl), and a bitter tastant, quinine, was
investigated for the first time. These experiments were conducted to
further explore the new paradigm of taste transduction that correlates
changes in the electrical behavior of lingual epithelia with neural
responses. In addition, the responses of rabbit tongue data were compared
with previously published data on dog and frog tongues. When increases in
short-circuit current (Isc) for rabbit tongue induced by hyperosmotic
concentrations of several salts were compared, the following sequence was
found: KCl greater than NH4Cl greater than NaCl greater than TEACl. These
results are consistent with previously published integrated chorda tympani
responses (ICTR) as well as behavioral studies that showed that rabbits
prefer KCl to NaCl with their natural diet. Pharmacological studies using
ouabain and amiloride suggest that K and Na are traversing rabbit tongue
through different pathways. The maximal stimulation of Isc by D-glucose and
sucrose (in 50 mM NaCl) was significantly smaller than those measured for
KCl and NaCl. The rabbit tongue was sensitive to HCl at concentrations less
than 1 mM in agreement with ICTR measurements.
