SCN2B in the Rat Trigeminal Ganglion and Trigeminal Sensory Nuclei.

The beta-2 subunit of the mammalian brain voltage-gated sodium channel (SCN2B) was examined in the rat trigeminal ganglion (TG) and trigeminal sensory nuclei. In the TG, 42.6 % of sensory neurons were immunoreactive (IR) for SCN2B. These neurons had various cell body sizes. In facial skins and oral mucosae, corpuscular nerve endings contained SCN2B-immunoreactivity. SCN2B-IR nerve fibers formed nerve plexuses beneath taste buds in the tongue and incisive papilla. However, SCN2B-IR free nerve endings were rare in cutaneous and mucosal epithelia. Tooth pulps, muscle spindles and major salivary glands were also innervated by SCN2B-IR nerve fibers. A double immunofluorescence method revealed that about 40 % of SCN2B-IR neurons exhibited calcitonin gene-related peptide (CGRP)-immunoreactivity. However, distributions of SCN2B- and CGRP-IR nerve fibers were mostly different in facial, oral and cranial structures. By retrograde tracing method, 60.4 and 85.3 % of TG neurons innervating the facial skin and tooth pulp, respectively, showed SCN2B-immunoreactivity. CGRP-immunoreactivity was co-localized by about 40 % of SCN2B-IR cutaneous and tooth pulp TG neurons. In trigeminal sensory nuclei of the brainstem, SCN2B-IR neuronal cell bodies were common in deep laminae of the subnucleus caudalis, and the subnuclei interpolaris and oralis. In the mesencephalic trigeminal tract nucleus, primary sensory neurons also exhibited SCN2B-immunoreactivity. In other regions of trigeminal sensory nuclei, SCN2B-IR cells were very infrequent. SCN2B-IR neuropil was detected in deep laminae of the subnucleus caudalis as well as in the subnuclei interpolaris, oralis and principalis. These findings suggest that SCN2B is expressed by various types of sensory neurons in the TG. There appears to be SCN2B-containing pathway in the TG and trigeminal sensory nuclei.

Recognising facial onset sensory motor neuronopathy syndrome: insight from six new cases.

Facial onset sensory and motor neuronopathy (FOSMN) was first described in 2006 as an apparently sporadic neurodegenerative disease. Thirty cases have been reported to date. We summarise six new cases, highlighting the key clinical aspects of FOSMN and how to differentiate it from motor neurone disease (amyotrophic lateral sclerosis). Typically, patients present with slowly evolving numbness of the face followed by bulbar and proximal (neck and arm) weakness. However, one of our patients presented with a motor syndrome and his abnormal blink reflex studies provided a useful diagnostic clue. This extends the spectrum of the syndrome and emphasises that FOSMN should be considered in the differential diagnosis of motor neurone disease. We discuss the pathophysiology, diagnosis, prognosis and management considerations of FOSMN.

Induction of Heat Shock Protein 70 after Experimental Pulpal Exposure in Rats / 대한마취과학회지

BACKGROUND: Inducible heat shock protein 70s (iHSP70) are expressed by stressful stimuli that result in protein denaturation, and are thought to assist in the maintenance of cellular integrity and viability. In addition, iHSP70 is known to be a sensitive marker of neuronal injury. To my best knowledge, no previous studies have been documented on iHSP70 induction by nociceptive impulse transmission through peripheral nerves not by direct neural damage. The purpose of this study was to examine the hypothesis that iHSP70 can be expressed in the nervous system, which is related to the dental nociceptive pathway, by tooth pulp inflammation. METHODS: The pulp of rat mandibular molars was exposed. Animals were sacrificed at 1, 4, and 7 days after pulpal exposure, and the pulps were evaluated histologically. Also, iHSP70 levels were examined in the Gasserian ganglion (GG) and the trigeminal sensory nucleus (TSN). RESULTS: At 4 days after pulpal exposure, iHSP70 was significantly more expressed in the ipsilateral GG than in the contralateral GG. In the histological study, inflammation was found in the entire pulp tissue at 4 days. There were no significant differences in iHSP70 levels between the ipsilateral TSN and the contralateral TSN. Also, there were no significant differences in iHSP70 expression of GG and TSN between both sides at 1 and 7 days after pulpal exposure. CONCLUSIONS: These results suggest that iHSP70 can be expressed in the GG at 4 days after pulpal exposure by nociceptive impulses due to pulpal inflammation.

Ultrastructural analysis of glutamate immunoreactive primary afferent terminals in the trigeminal nucleus principalis and trigeminal nucleus oralis of the rat / 대한해부학회지

The present study was aimed to investigate the ultrastructure of the primary afferent terminals and whether glutamate may be a transmitter in these terminals within the trigeminal nucleus principalis and oralis of the rat. Labeling of primary afferent terminals was performed by the injection of the CTB-HRP into the trigeminal ganglion. Ultrastructural analysis and assessment of the glutamate like immunoreactivity by the immunogold technique was performed with the 66 peroxidased labeled boutons in the nucleus principalis and 62 in the nucleus oralis. Labeled boutons were presynaptic to dendritic shafts of the secondary neurons and postsynaptic to the pleomorphic vesicles containing endings (p-endings). Most of the labeled boutons made synaptic contact with the dendritic shafts. A little labeled boutons in the nucleus oralis but no in the nucleus principalis was observed to make synaptic contact with the soma or proximal dendrite. Most of the labeled boutons made synaptic contact with one to three neurofiles, but labeled boutons showing complex synaptic connections, such as those with five or more neurofiles, were more in principalis than in oralis. The average diameter of p-endings were smaller than that of labeled boutons (p<0.05). The diameter of the postsynaptic dendritic shafts were smaller in nucleus principalis than in nucleus oralis, thus indicated that the labeled boutons made synaptic contact with more distal portion of the postsynaptic dendrite in the nucleus principalis than in the nucleus oralis. The gold particle density over the labeled boutons were significantly higher than that over the p-endings and average tissue particle density. They were ranged from 110 to 430% of the average tissue particle density. These findings indicate that synaptic connection of the primary afferent terminals is organized in different manner in nucleus principalis and oralis, and suggest that glutamate is involved as neuroactive substance in the primary afferent terminals of the trigeminal system.