RT Journal Article
SR Electronic
T1 Specialized mechanoreceptor systems in rodent glabrous skin
JF bioRxiv
FD Cold Spring Harbor Laboratory
SP 337923
DO 10.1101/337923
A1 Jan Walcher
A1 Julia Ojeda-Alonso
A1 Julia Haseleu
A1 Maria K. Oosthuizen
A1 Ashlee H. Rowe
A1 Nigel C. Bennett
A1 Gary R. Lewin
YR 2018
UL http://biorxiv.org/content/early/2018/06/05/337923.abstract
AB Rodents use their forepaws to actively interact with their tactile environment. Studies on the physiology and anatomy of glabrous skin that makes up the majority of the forepaw are almost non-existent in the mouse. Here we developed a preparation to record from single sensory fibers of the forepaw and compared anatomical and physiological receptor properties to those of the hind paw glabrous and hairy skin. We found that the mouse forepaw skin is equipped with a very high density of mechanoreceptors; >3 fold more than hind paw glabrous skin. In addition, rapidly adapting mechanoreceptors that innervate Meissner’s corpuscles of the forepaw were several-fold more sensitive to slowly moving mechanical stimuli compared to their counterparts in the hind paw glabrous skin. All other mechanoreceptors types as well as myelinated nociceptors had physiological properties that were invariant regardless of which skin area they occupied. We discovered a novel D-hair receptor innervating a small group of hairs in the middle of the hind paw glabrous skin in mice. Glabrous D-hair receptors were direction sensitive albeit with an orientation sensitivity opposite to that described for hairy skin D-hair receptors. Glabrous D-hair receptors do not occur in all rodents, but are present in North American and African rodent species that diverged more than 65 million years ago. The function of these specialized hairs is unknown, but they are nevertheless evolutionarily very ancient. Our study reveals novel physiological specializations of mechanoreceptors in the glabrous skin that likely evolved to facilitate tactile exploration.