Figure 8.

Schematic drawing represents the postulated scenario of CGRP, a putative efferent transmitter, in taste buds. Two distinct types of taste cells are shown. During taste stimulation, ATP activates gustatory afferent fibers that propagate taste signals (small arrows) to the brain (Finger et al., 2005; Huang et al., 2007; Jaber et al., 2014; Vandenbeuch et al., 2015). Chemesthetic stimulation activates sensory afferent fibers that propagate signals centrally (double-headed arrows) and have the ability to release the stored transmitter. CGRP may be directly released from the activated afferent axon branches (orange curved arrow). The activation of the CGRP receptors triggers Presynaptic (Type III) cells to elevate intracellular Ca²⁺ transients and to secrete 5-HT, which inhibits ATP release from Receptor (Type II) cells via serotonergic signaling pathways (black symbol) (Huang et al., 2009). Collectively, the peptidergic actions in taste buds could necessarily imply the complex interplay between taste cells and peripheral sensory neurons that becomes more important during the processing of the gustatory information.