Consumption of SC45647 and Sucralose by Rats Selectively Bred for High and Low Saccharin Intake

The use of rats differing in the intake of sweet substances has highlighted some interesting parallels between taste preferences and drug self-administration. For example, rats selectively bred to consume high (HiS) or low (LoS) amounts of a 0.1% saccharin solution (when compared to water consumption), show corresponding differences across several measures of cocaine selfadministration (HiS > LoS). In this study, we measured whether the two strains also differ when response requirements are imposed for obtaining a sucrose reinforcer. Male HiS and LoS rats were measured for operant responding for sucrose pellets under fixed-ratio (FR) schedules of 1, 3, 5 and 10 and under a progressive-ratio (PR) schedule, during which the response requirement for each successive pellet increased exponentially. The effect of systemic naltrexone (0.3. 1 and 3 mg/kg) on PR responding for sucrose pellets was also tested. Under all FR and PR schedules, the numbers of pellets obtained by the LoS rats were significantly lower than those obtained by the HiS rats. Although the LoS weighed more than the HiS rats, this difference does not appear to explain differences in operant behavior. No strain differences in the effect of naltrexone were observed; the 3 mg/kg dose reduced the number of pellets obtained in both strains. Measures of locomotor activity taken prior to operant trials suggest that the differences in responding were not due to differences in general activity levels. These studies provide further characterization of the HiS and LoS rat lines by demonstrating that motivation to consume sucrose in greater in HiS than in LoS rats.

Section: Introductionmentioning

confidence: 67%

Section: Introductionmentioning

confidence: 99%

Operant responding for sucrose by rats bred for high or low saccharin consumption

Gosnell

Mitra

Avant

et al. 2010

“…Both male and female rats prefer sweet solutions to water [19;20]; however, female rats have been shown to display stronger preferences for both nutritive and non-nutritive sweet solutions than male rats [21]. Furthermore, female but not male rodents were shown to use sugary treats as a “comfort food” during periods of experimentally-induced stress [22].…”

Section: Introductionmentioning

confidence: 99%

Resistance of male Sprague–Dawley rats to sucrose-induced obesity: Effects of 18-methoxycoronaridine

Taraschenko

Maisonneuve

Glick

2011

Evidence suggests that the development of obesity in males and females might be mediated by distinct mechanisms, warranting different treatment approaches. In previous studies from this laboratory, a high sucrose diet induced excessive weight gain in female Sprague-Dawley rats and administration of a selective antagonist of α3β4 nicotinic receptors, 18-methoxycoronaridine (18-MC), prevented this form of obesity. In the present study similar parameters were studied in male rats by using an identical experimental protocol. The effects of repeated administration of 18-MC on body weight gain, deposition of fat, consummatory behavior and biochemical markers of obesity in male rats were also assessed. In contrast to females, males consuming ad libitum quantities of sucrose solution (30%) in combination with normal chow did not become obese; they did not gain excessive weight nor show excessive fat deposition. Repeated administration of 18-MC (20 mg/kg, i.p.) attenuated weight gain in both sucrose-consuming and control animals without altering food or fluid intake. The present results indicate that males and females are differentially responsive to high carbohydrate-diet obesity. Such gender disparities could be secondary to sex-specific alterations in cholinergic mechanisms of feeding and body weight regulation.

“…Our lab and others have demonstrated that rats display considerable variation in their acceptance of sucralose [12, 14, 32, 33], and that these differences are taste-driven [19]. However, the degree to which SP and SA differ in their perception of bitter- and sweet-like taste qualities remains unclear, as do the potential consequences of this differential perception of taste on caloric intake and diet choice.…”

Section: Discussionmentioning

confidence: 99%

Examination of the perception of sweet- and bitter-like taste qualities in sucralose preferring and avoiding rats

Loney

et al. 2015

Sucralose avoiding rats detect a bitter-like taste quality in concentrations of sucralose that are strongly preferred over water by sucralose preferring rats. Here, we investigated whether sucralose preferrers (SP) also detect a bitter-like quality in sucralose that may be masked by increased perception of sucralose’s sweet-like quality. A microstructural analysis of sucralose intake revealed that, at concentrations they avoided in preference tests, sucralose avoiders (SA) consumed smaller and fewer bouts of sucralose than SP. Interestingly, the concentration-dependent increase in sucralose preference in SP was not associated with larger bouts or increased lick rate, two measures that are expected to increase with increasing perceived sweetness. This suggests that SP can detect an aversive quality in sucralose, but this perception of a presumably bitter-like quality may be masked by increased salience of a sweet-like quality that sustains high levels of intake in SP. Further evidence for increased sweet-taste perception in SP, relative to SA, was obtained in a second study in which SP consumed more of a palatable sweet-milk diet than SA. These are the first data to suggest that SP are not blind to the bitter-like quality in sucralose, and that there may be differences in sweet-taste perception between SP and SA.