Evaluation of the T&T Olfactometer by Mapping c-fos Protein in an Olfactory Bulb

AbstractObjectives: Although in Japan the T&T olfactometer is most commonly used in patients suffering from smelling disorders, no scientific analysis has been performed so far. The objective of this study was to clarify whether the five odorants used in the T&T olfactometer are suitable or not. We mapped the glomeruli activated by the five test odorants employed in the T&T olfactometer. The expression of c-fos protein as a marker of neuronal excitation was monitored using an immunohistochemical technique. Study Design:The expression of c-fos protein in the rat olfactory bulb was investigated to determine what part of the olfactory system is activated by five odorants used in the T&T olfactometer. Methods:Each rat was isolated in a clean cage for 120 min to reduce the basal expression of c-fos protein. Each rat was fixed in the cage and exposed to one of five test odorants for 90 min. The expression of c-fos protein was measured using an immunohistochemical technique. Results:Each odorant activated numerous glomeruli and the patterns of distribution of activated glomeruli were specific to each odorant. Glomeruli in most regions of the bulb were activated by all five test odorants. Conclusion:We assume that in the T&T olfactometer the optimal ((five)) odorants are employed, because the glomeruli activated by those odorants showed unique patterns in the immunohistochemical assay.Copyright © 2002 S. Karger AG, Basel