TY - JOUR
T1 - Effects of amiloride on gustatory neural responses to salts in the frog
AU - Kitada, Yasuyuki
AU - Okuda-Akabane, Kazuhisa
AU - Mitoh, Yoshihiro
N1 - Copyright:
Copyright 2020 Elsevier B.V., All rights reserved.
PY - 2001
Y1 - 2001
N2 - In frogs, the glossopharyngeal nerve (GL) innervates taste receptors on almost the entire tongue. The mandibular branch (MBF) and palatine branch (PN) of the facial nerve innervate taste receptors on a very small area at the base of the tongue and on the palate, respectively. In the present study, effects of amiloride, an epithelial sodium channel blocker, on the tonic responses of the GL, MBF and PN in frogs to NaCl, LiCl, KCl and CaCl2 were investigated. In three nerves, amiloride at 0.5 mM, a relatively high concentration, did not affect the responses to 0.15 (concentration just above threshold)-0.5 M NaCl, 0.5 M LiCl and 0.3 M KCl, whereas it almost completely inhibited the response to 1.0 mM CaCl2. Amiloride may exert an inhibitory action on the response to CaCl2 by a competitive antagonism between Ca2+ and a monovalent cation of amiloride, because the response to Ca2+ is competitive inhibited by other cations such as Na+ and Mg2+. The lack of inhibitory effect of amiloride on the responses in the GL, MBF and PN to NaCl suggests that amiloride-sensitive sodium channels in the apical membrane of taste receptor cells are not involved in sodium taste transduction in frogs.
AB - In frogs, the glossopharyngeal nerve (GL) innervates taste receptors on almost the entire tongue. The mandibular branch (MBF) and palatine branch (PN) of the facial nerve innervate taste receptors on a very small area at the base of the tongue and on the palate, respectively. In the present study, effects of amiloride, an epithelial sodium channel blocker, on the tonic responses of the GL, MBF and PN in frogs to NaCl, LiCl, KCl and CaCl2 were investigated. In three nerves, amiloride at 0.5 mM, a relatively high concentration, did not affect the responses to 0.15 (concentration just above threshold)-0.5 M NaCl, 0.5 M LiCl and 0.3 M KCl, whereas it almost completely inhibited the response to 1.0 mM CaCl2. Amiloride may exert an inhibitory action on the response to CaCl2 by a competitive antagonism between Ca2+ and a monovalent cation of amiloride, because the response to Ca2+ is competitive inhibited by other cations such as Na+ and Mg2+. The lack of inhibitory effect of amiloride on the responses in the GL, MBF and PN to NaCl suggests that amiloride-sensitive sodium channels in the apical membrane of taste receptor cells are not involved in sodium taste transduction in frogs.
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U2 - 10.1093/chemse/26.9.1203
DO - 10.1093/chemse/26.9.1203
M3 - Article
C2 - 11705806
AN - SCOPUS:0035201001
VL - 26
SP - 1203
EP - 1210
JO - Chemical Senses
JF - Chemical Senses
SN - 0379-864X
IS - 9
ER -