Rie Fujiyama

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We examined the sour taste transduction mechanism in the mouse by applying whole cell patch-clamp technique to nondissociated taste cells from the fungiform papillae. Localized stimulation with 0.5 M NaCl and 25 mM citric acid (pH 3.0) of the apical membrane enabled us to obtain responses from single taste cells under a quasi-natural condition. Of 28 taste(More)
Acid and salt responses of taste cells induced by natural stimulation have not been investigated with exception of early studies with conventional microelectrode method, due to the toxicity of high concentration of salt or low pH of acid stimuli applied to isolated taste cells. This indicates that the application of rapid and localized stimulation to the(More)
The transduction mechanism of the conductance activated by saccharin was analysed in isolated bullfrog taste cells under whole-cell voltage-clamp. Bath application of 30 mM saccharin induced an inward current of -34 +/- 12 pA (mean +/- SEM, n = 10) at a membrane potential of -50 mV in 10 (23%) of 44 rod cells. The concentration-response relationship for the(More)
Using single channel recordings of the patch clamp method, we found first that cation channels were present in the bullfrog taste cell membranes. These channels were widely distributed over the taste cell membrane. The conductance examined with inside-out patches was 30.7 +/- 5.7 pS (mean +/- S.D., n = 13). The permeability ratio of the cation channel to(More)
The transduction mechanism of salt-induced responses of mouse taste cells was investigated using the patch clamp and the local stimulation techniques under quasi-natural conditions. Apically applied NaCl induced a voltage-independent current, which was partially suppressed by amiloride and Cd2+. In contrast, apically applied 0.5 M KCl induced an inwardly(More)
When the glossopharyngeal (GP) nerve of the frog was stimulated electrically, electropositive slow potentials were recorded from the tongue surface and depolarizing slow potentials from taste cells in the fungiform papillae. The amplitude of the slow potentials was stimulus strength- and the frequency-dependent. Generation of the slow potentials was not(More)
The membrane properties of isolated frog parathyroid cells were studied using perforated and conventional whole-cell patch-clamp techniques. Frog parathyroid cells displayed transient inward currents in response to depolarizing pulses from a holding potential of -84 mV. We analyzed the biophysical properties of the inward currents. The inward currents(More)
When the glossopharyngeal nerve (GP) in the frog was strongly stimulated electrically, slow potentials were elicited from the tongue surface and taste cells in the fungiform papillae. Injection of atropine completely blocked these slow potentials. The present and previous data indicate that the slow potentials induced in the tongue surface and taste cells(More)
The amiloride-sensitive and -insensitive components of salt- and acid-induced responses in C57BL/6 and BALB/c mouse nondissociated taste cells were examined using the whole-cell clamp technique and localized taste stimulation method. Both amiloride-sensitive and -insensitive components were involved in a salt-induced depolarizing response. The taste cells(More)
The effect of arginine vasopressin (AVP) on the membrane properties was analyzed in isolated bullfrog taste cells using a perforated whole-cell patch-clamp technique. AVP (100 nM) induced three kinds of responses in rod-type taste cells: appearance of inward current, inhibition of voltage ramp-induced outward current and enhancement of the outward current.(More)