The evolution of the sensory systems has let mammals develop complicated tactile end organs to enable sophisticated sensory tasks including social interaction, environmental exploration and tactile discrimination. The Merkel disc, a main type of tactile end organs consisting Merkel cells and Aβ-afferent endings, are highly abundant in fingertips, touch domes and whisker hair follicles of mammals. It has high tactile acuity for an object’s physical features such as texture, shape and edges. Mechanisms underlying the tactile function of Merkel discs are obscured as how Merkel cells transmit tactile signals to Aβ-afferent endings leading to tactile sensations. Using the rodent whisker hair follicle as a model tactile sensory organ, our recent studies (Ikeda et al. Cell 157:664-75, 2014; Chang et al., PANS 113 E5491-500, 2016) have demonstrated that tactile signals are transduced via Piezo2 channels into Ca2+ action potentials on Merkel cells. The excitatory signals on Merkel cells are then transmitted by serotonin to evoke Aβ-afferent impulses to result in tactile behavioral responses. The involvement of Piezo2 and serotonin in tactile functions shall have implications in sensory disorders such as numbness and tactile allodynia.