The long-term goal of this project is to provide an integrated psychophysical description of the human ability to sense chemical irritants via she trigeminal nerve. Guided by the view that the sensitivity to irritants derives from elements of the nociceptive and thermal senses present in all types of skin, the proposed research will investigate the extent to which this common neural basis influences chemosensory perception throughout the trigeminal system. This objective will be pursued by (1) measuring the sensitivity to irritants across the full diversity of trigeminal regions--the oral cavity, nasal cavity, face and eyes--on a large number of subjects, and inferring from those data the-contributions of local and systemic factors to individual differences; (2) measuring individual differences in sensitization and desensitization produced by two different irritants on two kinds of skin, thus determining whether these phenomena vary locally or systemically; (3) providing the first quantitative investigation of long-term capsaicin desensitization in the trigeminal region and determining if menthol, which was recently found to produce short-term desensitization, has similar long-term hyperalgesic effects; and (4) investigating the role of counterirritation, a form of masking intrinsic to the nociceptive system, on the perception of multiple and/or spatially complex irritant stimuli within the trigeminal field. As well as providing new information about trigeminal chemoreception and the extent to which it may be influenced by systemic (nociceptive) factors, the proposed research will employ a battery of new psychophysical procedures that could prove useful for assessing the incidence, and nature of apparent hypersensitivity syndromes such as contact dermatitis and multiple chemical sensitivities. In addition, studies of long-term desensitization and counterirritation will provide basic information about how these two phenomena may impact on applied issues ranging from the perception and liking of hot and spicy foods to the use of chemical irritants as topical analgesics.

Agency
National Institute of Health (NIH)
Institute
National Institute on Deafness and Other Communication Disorders (NIDCD)
Type
Research Project (R01)
Project #
5R01DC002499-04
Application #
2014559
Study Section
Sensory Disorders and Language Study Section (CMS)
Project Start
1995-01-01
Project End
1998-12-31
Budget Start
1997-01-01
Budget End
1997-12-31
Support Year
4
Fiscal Year
1997
Total Cost
Indirect Cost
Name
John B. Pierce Laboratory, Inc.
Department
Type
DUNS #
City
New Haven
State
CT
Country
United States
Zip Code
06519