Generalization in olfactory detection of chemical cues containing carbonyl functions by tiger salamanders (Ambystoma tigrinum).

Tiger salamanders generalize behaviorally between carbonyl-containing odorants (e.g., aldehydes or cycloalkanones). However, responding does not generalize from such odorants to stimulus compounds with comparable molecular shapes and dimensions but different functional groups. Discrimination between aldehydes and a ketone is temporarily impaired by two-step covalent modification of the olfactory epithelium. Two-step modification of the olfactory epithelia also impairs, but does not obliterate, olfactory detection, and generalization persists even during the period of impairment. These results are interpreted as implying the existence of carbonyl-binding, "generalist" olfactory receptors in addition to other classes of "generalist" receptors that are not affected by two-step modification. Generalization is inferred to require overlap in the response profile of more than one class of receptor.