Experimental Brain Research

, Volume 201, Issue 1, pp 59–64 | Cite as

Functional properties of low-threshold mechanoreceptive afferents in the human labial mucosa

Research Article

Abstract

We used microneurography to investigate the functional properties of low-threshold mechanoreceptive afferents innervating the oral mucosa of the inside of the lower lip. Impulse responses were recorded from the inferior alveolar nerve of four human subjects. The threshold force and receptive field boundaries were identified for 19 single mechanoreceptive afferents using thin filaments (von Frey hairs) that applied known forces to the mucosa. Most of the receptive fields were located close to the corners of the mouth. Twelve of the afferents were slowly adapting (SA) and the remaining seven units were fast adapting (FA). Two types of slowly adapting responses were observed, SA I and SA II. Four of the six SA II units were spontaneously active. The geometric mean value of the receptive field sizes was 4.20 mm2 for the SA I units, 5.65 mm2 for the SA II units, and 5.60 mm2 for the FA I units. None of the FA afferents showed response properties characteristic of Pacinian-corpuscle type afferents (FA II units). All afferents showed low force threshold between 0.06 and 1 mN. The properties of the mechanoreceptors supplying the human labial mucosa appear more similar to those of the vermilion and facial skin of the lower lip than those supplying the mucosa of the dorsal tongue.

Keywords

Mechanoreceptor Microneurography Trigeminal nerve Tactile sensibility Oral mucosa 

Notes

Acknowledgments

This work was supported by grants from the Swedish Medical Research Council and Karolinska Institutet.

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Copyright information

© Springer-Verlag 2009

Authors and Affiliations

  1. 1.Department of Dental MedicineKarolinska InstitutetHuddingeSweden
  2. 2.Department of Prosthodontics, Center for Neurosensory DisordersUniversity of North Carolina at Chapel HillChapel HillUSA

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