Pulpar tooth injury induces plastic changes in S100B positive astroglial cells in the trigeminal subnucleus caudalis

Pain in humans constitutes a complex perception that involves peripheral tissues, nerves and the central nervous system. The glia is thought to be involved in the propagation and modulation of painful stimuli, as well as for the neurotransmission and plastic changes. In this work, an intermediate inflammatory nociceptive stimulus was generated after the exposure of the pulp in the left mandibular first molar. We analyzed the relationship between this tooth injury and the S100B expression in the trigeminal subnucleus caudalis. A significant difference of S100B immunoreactivity between the ipsilateral and the contralateral side could be observed at the 4th postoperative day. Besides, S100B positive-astrocytes located in the ipsilateral side showed an increase in their arborization, but not in the level of expression of the S100B protein. Our findings suggest that a unilateral peripheral nociceptive stimulus produces modifications in S100B positive-astrocytes in both sides of the trigeminal subnucleus caudalis.