Je. Comettomuniz et Ws. Cain, RELATIVE SENSITIVITY OF THE OCULAR TRIGEMINAL, NASAL TRIGEMINAL AND OLFACTORY SYSTEMS TO AIRBORNE CHEMICALS, Chemical senses, 20(2), 1995, pp. 191-198
We measured thresholds for eye irritation and odor in homologous serie
s of alcohols (ethanol, 1-butanol, 1-hexanol and l-octanol), ketones (
2-propanone, 2-pentanone, 2-heptanone and 2-nonanone), and alkylbenzen
es (toluene, ethyl benzene and propyl benzene). Eye irritation thresho
lds were well above odor thresholds for all series. Both sensory thres
holds declined with carbon chain length, a trend that has implicated l
ipophilicity in the potency of these and related stimuli. Eye irritati
on thresholds were remarkably close to nasal pungency thresholds obtai
ned previously in persons lacking olfaction (i.e. anosmics). The agree
ment between the two thresholds implies that, despite differences in t
he mucus layer at the two sites and in the epithelial tissue itself, t
here is remarkable similarity at the site of stimulation. As a practic
al matter, the eyes could serve as the sites to assess potency for ind
uction of nasal pungency, an assessment previously limited to testing
anosmics. Presumably for our brief stimulus presentations (1-3 s), the
differences between ocular and nasal mucosae have little relevance to
chemical sensitivity. Studies of the ability of homologous chemical s
eries to evoke threshold eye irritation, nasal pungency and odor not o
nly have practical value, but also can help to define the physicochemi
cal properties of the receptor and perireceptor biophases.