Postnatal development of substance P-immunoreaction in the trigeminal caudalis of neonatally capsaicin-treated mice

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Author(s)

    • AITA Megumi
    • Division of Oral and Maxillofacial Surgery, Niigata University Graduate School of Medical and Dental Sciences
    • MAEDA Takeyasu
    • Oral Anatomy, Niigata University Graduate School of Medical and Dental Sciences
    • TAKAGI Ritsuo
    • Division of Oral and Maxillofacial Surgery, Niigata University Graduate School of Medical and Dental Sciences
    • SEO Kenji
    • Dental Anesthesiology, Niigata University Graduate School of Medical and Dental Sciences

Abstract

The trigeminal subnucleus caudalis (Vc) is a critical relay site for processing nociceptive afferent input from the orofacial area in addition to its modulation by neuroplastic change. Although an administration of capsaicin in neonates induces a selective destruction of substance P (SP)-immunoreactive nerve fibers, little information is available regarding its detailed effects on the Vc, particularly during postnatal development. The present study examined postnatal changes in the distribution of SP in the Vc and trigeminal ganglion (TG) by immunohistochemical techniques in naïve (NV) and neonatally capsaicin-treated (CP) mice, combined with a quantitative analysis. The neonatal mice received a single subcutaneous injection of capsaicin (50 mg/kg) at 48 hours after birth. The neural density of the SP-immunoreaction decreased to approximately a quarter of that in 1-week-old NV mice but increased to three-quarters of that in the NV in the superficial area after postnatal week 2. A double staining with SP and myelin basic protein confirmed the absence of any SP-immunoreaction in the myelinated nerve fibers in both NV and CP mice. The SP-immunoreaction never overlapped with non-peptidergic IB4-labeled neurons in the Vc and TG of either group. Neither the size distribution of SP-positive neurons nor their relative ratio in the TG differed between NV and CP mice at the ages of postnatal weeks 1 and 8. These findings indicate two putative origins for the emergent SP-immunoreaction in the superficial layer of the Vc of the CP mice: the surviving trigeminal neurons with SP against capsaicin treatment and/or intrinsic neurons/interneurons in the Vc without SP under normal conditions.

Journal

  • Archives of Histology and Cytology

    Archives of Histology and Cytology 68(4), 311-320, 2005-12-01

    International Society of Histology and Cytology

References:  30

Cited by:  1

Codes

  • NII Article ID (NAID)
    10017160871
  • NII NACSIS-CAT ID (NCID)
    AA1068990X
  • Text Lang
    ENG
  • Article Type
    Journal Article
  • ISSN
    09149465
  • Data Source
    CJP  CJPref  J-STAGE 
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