Fig. 3.

Cholinergic urethral brush cells express components of the canonical taste transduction cascade. (A) Male urethra. ChAT-eGFP (green) and TRPM5 (orange) are expressed by the same cell; nuclei are labeled in blue with DAPI. (B) Female urethra. An obliquely oriented ChAT-eGFP cell is immunolabeled for PLCβ2. In this section plane, no connection of this cell to the urethral lumen is visible. (C) Male urethra, diverticular region. α-Gustducin (αGust)⁺ ChAT-eGFP cell extending a slender process toward the lumen. (D) Schematic drawing of the canonical transduction cascade known from taste buds (based upon information published in ref. 49) depicting the position and role of α-gustducin, PLCβ2, and TRPM5 in this process. DAG, diacylglycerol; ER, endoplasmic reticulum; IP₃, inositol trisphosphate; TasR, taste receptor.