Human odor intensity perception: correlation with frog epithelial adenylate cyclase activity and transepithelial...

Although a number of odorants are hypothesized to depolarize frog olfactory receptor cells by binding to ciliary glycoproteins which activate membrane-bound G-proteins to induce adenylate cyclase-mediated increases in intracellular cAMP (cyclic adenosine 3',5'-monophosphate), it is not known whether these odorants influence human odor perception via similar mechanisms. In this paper we present evidence derived from odor attribute ranking and multidimensional scaling procedures that the perceived intensity of such odorants to humans is correlated with (a) the amount of adenylate cyclase activity they induce in an in vitro frog olfactory cilia preparation and (b) the magnitude of their influence on the frog transepithelial voltage response or electro-olfactogram (EOG). These observations are in accord with the hypothesis that the perception of the intensity of some odors by humans is associated with cAMP-related epithelial processes and imply that remarkable homologies exist between the intensity-related olfactory receptor mechanisms of frog and man.