title: In situ measurement of vapor uptake in the rodent upper respiratory tract.
abstract: The response of respiratory tract tissue target sites to inhaled vapors depends on the amount of inhaled vapor that is delivered to those sites. Direct measurement of vapor absorption within a specific airway of the living animal requires that the airway be isolated, which currently can only be performed on the upper airways. Towards this end, the upper respiratory tract (all airways anterior to the larynx) is surgically isolated in the anesthetized rat by tracheostomy and insertion of two endotracheal tubes, one leading anteriorly and the other posteriorly. The surgically manipulated animal is then placed in a nose-only inhalation chamber and test-vapor-laden air is drawn through the isolated upper airways under defined air flow conditions via the anterior endotracheal tube. The animal spontaneously respires clean air into the lungs during this procedure via the posterior endotracheal tube. The concentration of test vapor in air entering and the air exiting the upper airways is measured by gas chromatography, and the difference in concentrations provides a measure of vapor absorption in that site. A rich database is available on upper respiratory tract vapor absorption as measured by this methodology, to which newly obtained data can be compared. These data have been instrumental not only in understanding the regional airway toxicity of inspired vapors, but also for developing mathematical models to describe inhaled vapor dosimetry.
authors: Toxicology Program, Department of Pharmaceutical Sciences, University of Connecticut, Storrs, Connecticut, USA.
authors: John B
authors: JB
authors: Morris
authors: Joseph A
authors: JA
authors: Cichocki
authors: Gregory J
authors: GJ
authors: Smith
mesh_terms: D000042:Absorption; D000818:Animals; D006224:Cricetinae; D006168:Guinea Pigs; D019570:Inhalation Exposure / Q000009:adverse effects / Q000032:analysis*; D051379:Mice; D051381:Rats; D020545:Respiratory Mucosa / Q000187:drug effects / Q000378:metabolism*; D012137:Respiratory System / Q000187:drug effects / Q000378:metabolism*; D018675:Toxicity Tests / Q000295:instrumentation / Q000379:methods*; D014520:Urethane / Q000378:metabolism* / Q000633:toxicity; D014835:Volatilization
chemical_list: D014520:Urethane