N. Badiaelder et al., TASTE REACTIVITY IN RATS SELECTIVELY BRED FOR HIGH VS LOW SACCHARIN CONSUMPTION, Physiology & behavior, 59(4-5), 1996, pp. 749-755
Rats selectively bred for high (HiS) vs. low (LoS) saccharin consumpti
on were compared on taste reactivity responses to 0.1% saccharin befor
e and after continuous access to 0.1% saccharin. The rats were also te
sted with other saccharin concentrations (0.01-0.3%) before and after
the consumption test. Finally, all rats were tested for reactivity to
0.1 M sucrose, 0.0001 M quinine hydrochloride, and a sucrose + quinine
mixture. HiS rats ingested more saccharin than did LoS rats, but the
groups did not differ in total ingestive or total aversive reactivity
on any of the taste tests. When aversive reactivity was analyzed furth
er to distinguish passive drip from other, more active responses, HIS
rats made more active responses than LoS rats; the latter showed a con
sistent tendency to passive drip more than HiS rats. Overall, aversive
responding decreased and ingestive responding increased as saccharin
concentration rose and from the first to the second concentration seri
es. Because the brain stem-mediated hedonic evaluation of tastes by Hi
S and LoS rats appears to be similar, the difference in saccharin cons
umption must be mediated by psychological processes whose neural subst
rates lie above the brain stem.