Figure 3.

Modulatory effect of external pH (pH₀), elevated temperature, capsaicin (CAP), resiniferatoxin (RTX), and ethanol (ETH) on the Bz-insensitive NaCl CT response. (A) Rat tongue was first stimulated with R and then with N + Bz containing 0.25% GalA-MRP maintained at 23 °C. Both R and N + Bz + GalA-MRP solutions were adjusted to pHs between 4.1 and 9.1 (Table 1). The mean ± standard error of the mean (SEM) values of the normalized phasic (open circle) tonic (filled circles) CT response from 3 animals are plotted as a function of pH₀. (B) Rat tongue was first stimulated with R and then with N + Bz solutions containing 0.25% GalA-MRP maintained at 23 °C, 30.2 °C, 38.6 °C, and 41.9 °C (Table 1) using Stimulus Series 3 protocol (see Materials and methods). The normalized mean ± SEM values of the tonic CT response from 3 animals are plotted as a function of temperature. *P < 0.0001. (C) Rat tongue was first stimulated with R and then with N + Bz, N + Bz + CAP (20 × 10⁻⁶ M), N + Bz + RTX (0.25 × 10⁻⁶ M), N + Bz + 0.25% GalA-MRP, N + Bz + CAP + GalA-MRP, and N + Bz + RTX + GalA-MRP maintained at 23 °C (Table 1). The mean ± SEM values of the mean normalized tonic CT response from 3 animals are plotted in the presence of above TRPV1t modulators. *P < 0.0001. (D) Rat tongue was first stimulated with R and then with N + Bz, N + Bz + 20% ETH, N + Bz + 40% ETH, N + Bz + 0.25% GalA-MRP, N + Bz + 20% ETH + GalA-MRP, and N + Bz + 40% ETH + GalA-MRP maintained at 23 °C (Table 1). The mean SEM values of the normalized tonic CT response from 3 animals are plotted in the absence and presence of above TRPV1t modulators. *P < 0.0001.