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Toluene diisocyanate enhances substance P in sensory neurons innervating the nasal mucosa.

Authors
Hunter-DD; Satterfield-BE; Huang-J; Fedan-JS; Dey-RD
Source
Am J Respir Crit Care Med 2000 Feb; 161(2)(Pt 1):543-549
NIOSHTIC No.
20020706
Abstract
Inhalation of irritants, such as toluene diisocyanate (TDI), stimulates substance P (SP) release from peripheral processes of sensory neurons innervating the airways. The purpose of this study was to determine if TDI inhalation affects intraneuronal levels of SP and preprotachykinin (PPT) messenger RNA (mRNA) in the sensory neurons of the trigeminal ganglion (TG) which innervate the nasal epithelium. The nasal cavity of Fisher-344 rats was instilled with rhodamine-labeled latex microspheres. Ten days later, the rats were exposed to 60 ppb of 2,4-2,6-TDI vapor for 2 h. The TG were removed 1, 12, 24, 48, 72, and 96 h after TDI treatment and prepared for SP immunocytochemistry and PPT in situ hybridization. SP nerve fiber density in nasal epithelium was significantly increased 12, 24, and 48 h after TDI exposure. The proportion of microsphere-labeled cell bodies expressing high levels of SP immunoreactivity was decreased at 24 h but was increased above controls at 48 and 72 h. The proportion of microsphere-labeled cell bodies expressing high levels of PPT mRNA was increased above control levels at 24 and 48 h. The percentage of leukocytes observed in nasal lavage fluid was significantly increased 12, 24, 48, and 72 h after inhalation. These studies indicate that SP production in TG neurons projecting to the nasal epithelium is transiently increased after TDI exposure, suggesting that TDI inhalation not only causes SP release but also increased intraneuronal neuropeptide levels. Increased neuronal SP levels may be involved in maintaining neurogenic inflammation or the development of airway hyperresponsiveness.
Keywords
Toluenes; Inhalation-studies; Airway-obstruction; Nasal-disorders; Laboratory-animals; Animals; Animal-studies; Exposure-assessment; Cellular-reactions; Cell-function
Contact
Richard D. Dey, Ph.D, Department of Anatomy, P.O. Box 9128, Morgantown, WV 26506-9128
CODEN
AJCMED
CAS No.
108-88-3
Publication Date
20000201
Document Type
Journal Article
Email Address
rdey@wvu.edu
Fiscal Year
2000
NTIS Accession No.
NTIS Price
Issue of Publication
2
ISSN
1073-449X
NIOSH Division
HELD
Source Name
American Journal of Respiratory and Critical Care Medicine
State
WV
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