Taste qualities of solutions preferred by hamsters

Molecules of diverse chemical structure are sweet to humans and several lin es of evidence (genetic, physiological, behavioral) suggest that there may be distinct sweet perceptual qualities. To address how many perceptual cate gories these molecules elicit in hamsters (Mesocricetus auratus), we studie d patterns of generalization of conditioned taste aversions for seven sweet eners. 100 mM sucrose, 320 mM maltose, 32 mM D-phenylalanine, 3.2 mM sodium saccharin, 16 mM calcium cyclamate, 10 mM dulcin and 32 mM sodium m-nitrob enzene sulfonate. Each stimulus was preferred versus water in two-bottle in take tests and stimulated the chorda tympani nerve. For each of seven exper imental groups the conditional stimulus (CS) was a sweetener and for the co ntrol group the CS was water. Apomorphine.HCl was injected i.p. after a CS was sampled and, after recovery, test stimuli (TS) were presented for 1 h d aily. The intake (ml) of each TS consumed by experimental animals was compa red with mean TS intake by the control group. Learned aversions for 18/21 s timulus pairs cross-generalized, resulting in a single cluster of generaliz ation patterns for the seven stimuli. Cross-generalization failures (maltos e-cyclamate, maltose-sucrose, cyclamate-NaNBS) may be the consequence of pa rticular stimulus features (e.g. salience, cation taste), rather than the a bsence of a 'sucrose-like' quality. The results are consistent with a singl e hamster perceptual quality for a diverse set of chemical structures that are sweet to humans.