Nakao Yoshiki, Tateno Katsumi, Ohtubo Yoshitaka
Graduate School of Life Science and Systems Engineering, Kyushu Institute of Technology, Kitakyushu, Japan.
Front Physiol. 2022 May 25;13:883372. doi: 10.3389/fphys.2022.883372. eCollection 2022.
The receptor potentials of taste receptor cells remain unclear. Here, we demonstrate that taste receptor cells generate oscillating depolarization ( = 7) with action potentials in response to sweet, bitter, umami, and salty taste substances. At a lower concentration of taste substances, taste receptor cells exhibited oscillations in membrane potentials with a low frequency and small magnitude of depolarization. Although the respective waves contained no or 1-2 action potentials, the taste receptor cells generated action potentials continuously in the presence of taste stimuli. Both the frequency and magnitude of oscillations increased when the concentration was increased, to 0.67-1.43 Hz ( = 3) and Δ39-53 mV ( = 3) in magnitude from -64.7 ± 4.2 to -18.7 ± 5.9 mV, which may activate the ATP-permeable ion channels. In contrast, a sour tastant (10-mM HCl) induced membrane depolarization (Δ19.4 ± 9.5 mV, = 4) with action potentials in type III taste receptor cells. Interestingly, NaCl (1 M) taste stimuli induced oscillation ( = 2) or depolarization (Δ10.5 ± 5.7 mV at the tonic component, = 9). Our results indicate that the frequency and magnitude of oscillations increased with increasing taste substance concentrations. These parameters may contribute to the expression of taste "thickness."
味觉受体细胞的感受器电位仍不清楚。在此，我们证明味觉受体细胞在对甜味、苦味、鲜味和咸味物质作出反应时会产生伴有动作电位的振荡性去极化（= 7）。在较低浓度的味觉物质作用下，味觉受体细胞表现出膜电位的振荡，频率较低且去极化幅度较小。尽管各个波中没有动作电位或仅有1 - 2个动作电位，但味觉受体细胞在味觉刺激存在时持续产生动作电位。当浓度增加时，振荡的频率和幅度均增加，频率增加到0.67 - 1.43 Hz（= 3），幅度从 - 64.7 ± 4.2 mV增加到 - 18.7 ± 5.9 mV，变化幅度为Δ39 - 53 mV（= 3），这可能会激活ATP可通透的离子通道。相比之下，酸味剂（10 mM HCl）在III型味觉受体细胞中诱导出伴有动作电位的膜去极化（Δ19.4 ± 9.5 mV，= 4）。有趣的是，NaCl（1 M）味觉刺激诱导出振荡（= 2）或去极化（在紧张成分处为Δ10.5 ± 5.7 mV，= 9）。我们的结果表明，振荡的频率和幅度随着味觉物质浓度的增加而增加。这些参数可能有助于味觉“浓度”的表达。
