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Assessment of Morphine-induced Hyperalgesia and Analgesic Tolerance in Mice Using Thermal and Mechanical Nociceptive Modalities
Published on: July 29, 2014
Subchronic inhalation toxicity of morpholine in rats
Summary
High-level morpholine inhalation caused nasal irritation and damage in rats. Lower doses showed minimal effects, indicating a dose-dependent toxicity for this chemical.
Area of Science:
- Toxicology
- Inhalation Toxicology
- Respiratory System Research
Background:
- Morpholine is a widely used industrial chemical.
- Understanding its inhalation toxicity is crucial for occupational safety.
Purpose of the Study:
- To evaluate the subchronic inhalation toxicity of morpholine in Sprague-Dawley rats.
- To identify dose-dependent effects and target organs.
Main Methods:
- Rats were exposed to 25, 100, or 250 ppm morpholine for 6 hours/day, 5 days/week, for 13 weeks.
- Histopathological examination of nasal tissues and other organs was performed.
- Clinical chemistry, hematology, and organ weights were assessed.
Main Results:
- The 250-ppm morpholine group exhibited significant irritant effects, including nasal discharge, salivation, and histopathological changes in the nasal cavity (maxilloturbinates, nasal septum).
- Lesions included focal erosion, squamous metaplasia, and increased severity of chronic murine pneumonia.
- The 100-ppm group showed minimal effects (focal necrosis in two females), while the 25-ppm group had no observed compound-related effects.
- No significant effects on body weight, clinical chemistry, hematology, or organ weights were noted.
Conclusions:
- Morpholine inhalation toxicity is dose-dependent, with significant nasal and respiratory effects observed at 250 ppm.
- The nasal turbinates and septum are primary targets for morpholine-induced damage.
- Lower exposure levels (25 and 100 ppm) demonstrated limited toxicity in this study.
