Epidermal Merkel cells sense touch, but how they activate sensory neurons is not clear. Now, Hoffman et al. demonstrate that Merkel cells manufacture presynaptic and catecholamine-synthesis machinery, and can package and release a neurotransmitter analogue into and from vesicles, respectively. Noradrenaline evoked action potentials in Merkel cell afferents, and a β2-adrenergic antagonist blocked touch-evoked neural responses. Thus, Merkel cells release noradrenaline across synapses to activate sensory neurons.
Hoffman, B. U. et al. Merkel cells activate sensory neural pathways through adrenergic synapses. Neuron https://doi.org/10.1016/j.neuron.2018.10.034 (2018)