The Center for Alternatives to Animal Testing is an academic center affiliated with the Division of Toxicological Sciences in the Department of Environmental Health Sciences of the Johns Hopkins University Bloomberg School of Public Health.

 

Johns Hopkins School of Public Health

Research Grants 2000-2001

Sensory Irritant Screening Using a Stable Cell Line Expressing the Vanilloid Receptor

Thomas K. Baumann, PhD
Oregon Health Sciences

When animals (including humans) are exposed to irritant chemicals in the air, they change the pattern of breathing in order to protect the lungs. Decrease in breathing rate in mice has for many years been used as a behavioral test for measuring sensory irritancy. The test forms the basis for setting a safe limit for human exposure to airborne chemicals. While very simple, the inhalation test requires exposing live animals to what may be unpleasant or harmful chemicals. We wish to develop an alternative method for sensory irritant screening. Studies of sensory irritation in mice showed that sensory irritation is a process which is mediated by a receptor protein. Experimental evidence suggests that the receptor is very similar to a protein which is present in sensory nerve cells and is activated by capsaicin (the irritant chemical which makes red pepper taste hot). The DNA sequence which codes for the capsaicin receptor (called the vanilloid receptor) in neurons has recently been deciphered and cloned. The goal of this research proposal is to insert the DNA and express the vanilloid receptor protein in a non-neuronal cell line. In contrast to neurons, non-neuronal cells have the ability to multiply. Once stable expression of the vanilloid receptor is achieved, and the new sensory irritant assay validated, then the cells could be grown for many generations and used to test chemicals for sensory-irritant potential. This assay would avoid exposing animals to chemicals or sacrificing animals to make nerve cell cultures for sensory irritant screening.