The effects of @entity7183 depletion induced by neonatal @entity2951 treatment on the functional properties of vibrissa-sensitive low-threshold mechanoreceptive (LTM) neurons in the @entity35 trigeminal nucleus principalis were examined in adult @entity35 . Neonatal @entity35 were injected either with @entity2951 or its vehicle within 48 h of birth. The depletion of unmyelinated afferents was confirmed by the significant decrease in plasma extravasation of Evan's blue dye induced in the hindlimb skin of @entity2951 -treated @entity35 by cutaneous application of mustard oil and by the significant @entity1930 . The mechanoreceptive field (RF) and response properties of 31 vibrissa-sensitive neurons in @entity2951 -treated @entity35 were compared with those of 32 vibrissa-sensitive neurons in control (untreated or vehicle-treated) @entity35 . The use of electronically controlled mechanical stimuli allowed quantitative analysis of response properties of vibrissa-sensitive neurons; these included the number of center- and surround-RF vibrissae within the RF (i.e., those vibrissae which when stimulated elicited >/=1 and <1 action potential per stimulus, respectively), the response magnitude and latency, and the selectivity of responses to stimulation of vibrissae in different directions with emphasis on combining both the response magnitude and direction of vibrissal deflection in a vector analysis. Neonatal @entity2951 treatment was associated with significant increases in the total number of vibrissae, in the number of center-RF vibrissae per neuronal RF, and in the percentage of vibrissa-sensitive neurons that also responded to stimulation of other types of orofacial tissues. Compared with control @entity35 , @entity2951 -treated @entity35 showed significant increases in the response magnitude to stimulation of surround-RF vibrissae as well as in response latency variability to stimulation of both center- and surround-RF vibrissae. @entity7183 depletion also significantly altered the directional selectivity of responses to stimulation of vibrissae. For neurons with multiple center-RF vibrissae, the proportion of center-RF vibrissae with net vector responses oriented toward the same quadrant was significantly less in @entity2951 -treated compared with control @entity35 . These changes in the functional properties of principalis vibrissa-sensitive neurons associated with marked depletion of @entity7183 afferents are consistent with similarly induced alterations in LTM neurons studied at other levels of the rodent somatosensory system, and indeed may contribute to alterations previously described in the somatosensory cortex of adult rodents. Furthermore, these results provide additional support to the view that C fibers may have an important role in shaping the functional properties of LTM neurons in central somatosensory pathways.

XXXX depletion alters response properties of neurons in trigeminal nucleus principalis.

@entity7183 :: ('10185', 'Species') :: ['C-fiber'] @entity1930 :: ('MESH:D020426', 'Disease') :: ['decrease of unmyelinated fibers in both the sciatic and infraorbital nerves'] @entity35 :: ('10116', 'Species') :: ['rat', 'rats'] @entity2951 :: ('MESH:D002211', 'Chemical') :: ['capsaicin']
@entity7183 :: (10185,Species) :: ['C-fiber']
