Newborns are hypersensitive to pain
Discovered the receptorial basis
Newborns feel pain
generated by mechanoreceptors in the skin more than adults. This
characteristic, according new studies, is not mediated through the activation
of low-threshold mechanoreceptors (LTMRs). Woodbury and Koerber (Widespread projections
from myelinated nociceptors throught the substantia gelatinosa provide novel
insights into neonatal hypersensitivity, J. Neurosci. 23, 601-610,
2003)
provide strong evidences that a particular kind of high threshold
mechanoreceptors (HTMRs) morphologically characterized are responsible for the
newborns hypersensitivity to pain. Woodbury and Koerber identified two subset
of HTMRs one of which generates projections for the whole dorsal horn laminae
and becomes increasingly active as the intensity of painful stimuli increases.
Suzanne Farley wrote a
brief discussion of the Woodbury and Koerber work in the current issue of
Nature Reviews Neuroscience, comparing the present paper with the previous one
published by the authors two years ago: J. Comp. Neurol. 436, 304-323 (2001).
BM&L-March 2003