MUTUAL CROSS-ADAPTATION OF THE VOLATILE STEROID ANDROSTENONE AND A NONSTEROID PERCEPTUAL ANALOG

Self- and cross-adaptation are believed to result from stimulation of the same olfactory sensory channels. These adaptation phenomena were studied after exposures to 5alpha-androst-16-en-3-one (androstenone) and a synthetic perceptual analog (DMCMC), viz. a racemic mixture of the isomers 4(R)-(4',4'-dimethyl-cyclohexyl)-2(R)-methylcyclohexanone and 4(S)-(4',4'-dimethylcyclohexyl)-2(S)-methylcyclohexanone. In Experiment 1, six subjects very sensitive to androstenone received four randomized sequences of six concentrations of four odorants (androstenone, DMCMC, amyl acetate, and Galaxolide(R); plus blanks) before and following adaptation to either androstenone or DMCMC. Exposure to each odorant resulted in self-adaptation. Measures of stimulus intensity and identification threshold revealed reciprocal cross-adaptation between androstenone and DMCMC, but no cross-adaptation to amyl acetate or Galaxolide. The degree of cross-adaptation was asymmetric; adaptation to DMCMC resulted in more complete adaptation to androstenone than vice versa. This asymmetry was apparently due to intensity differences; when stimuli were matched for intensity, the asymmetry disappeared (Experiment 2). These results demonstrate cross-adaptation for qualitatively similar, but not dissimilar, odors and suggest that androstenone and its perceptual analog DMCMC share the same sensory channels.