Amyl, isobutyl, butyl and cyclohexyl nitrites are volatile chemicals, which are abused by inhalation. Abuse of nitrite inhalants is particularly widespread among homosexuals. Epidemiological studies have identified heavy nitrite abuse as a risk factor in AIDS and also in Kaposi's sarcoma (KS) in AIDS patients. Data, obtained in this laboratory, suggests that mouse inhalation of isobutyl nitrite at levels approximating the exposure of habitual abusers severely compromises both antibody and cell-mediated immune mechanisms. The immunodeficiency was shown to target accessory cell functions, including cytokine synthesis. The present study will investigate the mechanisms of nitrite inhalant toxicity. The reactivity of nitrite inhalants will be examined to determine if they directly or indirectly modify the activity of critical cellular constituents through nitration or disruption of iron-sulfur centers. The induction of DNA breakage and impairment of the respiratory chain, the Krebs cycle enzyme, aconitase, and the nuclear binding factor, NF-kappa B will be examined. Inhalant-induced changes in NF-kappa B on signal transduction will be studied. Since previous studies indicated that inhalation exposure to the nitrites enhanced the production, but not transcription of the cytokine, tumor necrosis factor-alpha (TNF-alpha), nitrite effects on post-transcriptional processing, such as a translational efficiency and processing will be examined.

Agency
National Institute of Health (NIH)
Institute
National Institute on Drug Abuse (NIDA)
Type
Research Project (R01)
Project #
5R01DA006662-09
Application #
6150461
Study Section
Human Development Research Subcommittee (NIDA)
Program Officer
Sharp, Charles
Project Start
1991-06-01
Project End
2003-01-31
Budget Start
2000-02-01
Budget End
2003-01-31
Support Year
9
Fiscal Year
2000
Total Cost
$267,183
Indirect Cost
Name
University of Arkansas for Medical Sciences
Department
Microbiology/Immun/Virology
Type
Schools of Medicine
DUNS #
City
Little Rock
State
AR
Country
United States
Zip Code
72205
Soderberg, L S F; Ponnappan, U; Roy, A et al. (2004) Production of macrophage IL-1beta was inhibited both at the levels of transcription and maturation by caspase-1 following inhalation exposure to isobutyl nitrite. Toxicol Lett 152:47-56
Ponnappan, Usha; Yull, Fiona E; Soderberg, Lee S F (2004) Inhaled isobutyl nitrite inhibited macrophage inducible nitric oxide by blocking NFkappaB signaling and promoting degradation of inducible nitric oxide synthase-2. Int Immunopharmacol 4:1075-82
Soderberg, Lee S F; Ponnappan, Usha (2002) Cytotoxicity by nitrite inhalants is not related to peroxynitrite formation. Toxicol Lett 132:37-45
Ponnappan, U; Soderberg, L S (2001) Inflammatory macrophage nuclear factor-kappaB and proteasome activity are inhibited following exposure to inhaled isobutyl nitrite. J Leukoc Biol 69:639-44
Guo, G L; Rose, D; Flick, J T et al. (2000) Acute exposure to the abused inhalant, isobutyl nitrite, reduced T cell responsiveness and spleen cellularity. Toxicol Lett 116:151-8
Soderberg, L S; Roy, A; Flick, J T et al. (2000) Nitrite inhalants spontaneously liberate nitric oxide, which is not responsible for the immunotoxicity in C57BL/6 mice. Int J Immunopharmacol 22:151-7
Soderberg, L S (1999) Increased tumor growth in mice exposed to inhaled isobutyl nitrite. Toxicol Lett 104:35-41
Soderberg, L S; Flick, J T (1997) Acute blood toxicity of the abused inhalant, cyclohexyl nitrite. Int J Immunopharmacol 19:305-10
Soderberg, L S; Flick, J T; Barnett, J B (1996) Leukopenia and altered hematopoietic activity in mice exposed to the abused inhalant, isobutyl nitrite. Exp Hematol 24:848-53
Soderberg, L S; Flick, J T; Barnett, J B (1996) Acute inhalation exposure to isobutyl nitrite causes nonspecific blood cell destruction. Exp Hematol 24:592-6

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