What about physical contacts between epidermal keratinocytes and sensory neurons?

Recent studies have demonstrated that keratinocytes closely participate in sensory transduction, and therefore, intra-epidermal free nerve endings are not exclusive transducers of pain. This discovery implies the existence of close afferent communication from keratinocytes to sensory neurons. Although reciprocal interactions between keratinocytes and intra-epidermal free nerve endings via soluble mediators are well established, little attention has been paid to physical contacts between keratinocytes and intra-epidermal free nerve endings. This review proposes to consider the ultrastructural and functional knowledge of these contacts, in both human skin biopsies and keratinocyte-sensory neuron cocultures to speculate on the possible existence of synaptic contacts.