Figure 3.

Presynaptic (Type III) taste cells respond to CGRP. A, Taste cells were isolated from vallate papillae and their responses to CGRP recorded by Ca²⁺ imaging. Traces represent Ca²⁺ recordings from an isolated Receptor (Type II) cell (top traces) and an isolated Presynaptic (Type III) cell (bottom traces). Representative traces of an identified Presynaptic (Type III) taste cell depolarized by KCl (50 mm) (↓, KCl) followed by stimulation with CGRP (0.1 μm) (↓, CGRP). In marked contrast, a Receptor (Type II) cell showed a robust taste-evoked response (↓, taste) but absence of the response to CGRP. As shown in all records in this figure, KCl stimulation typically elicited more robust responses than for CGRP. B, Venn diagrams representing the relative proportions of Receptor (Type II) and Presynaptic (Type III) taste cells that responded to CGRP.