Do Merkel complexes initiate mechanical itch?

Area of Science:

• Neuroscience
• Dermatology
• Sensory Biology

Background:

• Itch is a common sensation, often disabling in chronic conditions.
• Mechanical itch and alloknesis are underappreciated aspects of itch pathophysiology.
• Recent advances have improved understanding of central nervous system mechanical itch pathways.

Purpose of the Study:

• To explore the role of Merkel complexes in initiating mechanical itch.
• To challenge the traditional view of Merkel complexes as solely touch receptors.
• To investigate Merkel complexes as potential tactile end organs for mechanical itch initiation.

Main Methods:

• Review of current literature on itch pathways and sensory receptors.
• Analysis of the known functions and components of Merkel complexes.
• Discussion of the potential role of Merkel complexes in encoding mechanical stimuli.

Main Results:

• Merkel complexes, expressing Piezo2, involve Merkel cells and SA1 Aβ-fibres (low threshold mechanoreceptors).
• These complexes have recently been identified as modulators of mechanical itch.
• They host SA1 Aβ-LTMRs, as well as A∂- and C-fibres, suggesting a role in itch initiation.

Conclusions:

• Merkel complexes should be considered potential tactile end organs initiating mechanical itch.
• Their modulatory abilities indicate they can detect and encode light mechanical stimuli leading to itch.
• This perspective broadens the understanding of mechanical itch initiation in health and disease.