Saccharin Intake Predicts Ethanol Intake in Genetically Heterogeneous Rats as Well as Different Rat Strains

Abstract

Saccharin and ethanol intakes were measured in seven strains of rats known to differ in their preferences for ethanol: The Fawn-Hooded (FH), alcohol-preferring (P) and Maudsley Reactive rats have been reported to drink ethanol voluntarily, whereas the alcohol-nonpreferring, Maudsley Nonreactive and Flinders Line (FSL and FRL) rats do not. Saccharin and ethanol intakes were highly correlated (r = +0.61) over all strains, with the FH rats drinking the most of both solutions. Correlation coefficients between pairs of drinking versus nondrinking rat strains were even higher. In a second experiment, genetically heterogeneous F2 progeny from cross-breeding the ethanol-preferring FH rats with the ethanol-nonpreferring Flinders Resistant Line (FRL) rats were studied. The results indicated a high positive correlation between saccharin and ethanol intakes (+0.65). These findings suggest that the association between saccharin and ethanol intakes previously reported in rat strains with different preferences for ethanol may have a similar genetic basis.

Ethanol Consumption and Taste Preferences in C57BL/6ByJ and 129/J Mice

“…12 A positive relationship between alcohol intake and sweet solution intake has also been found among other inbred strains of mice 5 and rats, 3,4 and within F 2 hybrids from ethanolpreferring and ethanol-nonpreferring rat strains. 3 Because these studies encompass a wide variety of nutritive and nonnutritive sweeteners, some of which are believed to have no postingestive effects, the results support the contention there is a genetically determined link between alcohol intake and sweet taste perception.Based on findings that the taste of alcohol has a bitter component to rats, 2 and that an association between a predisposition to alcoholism and lower sensitivity to bitter was found in humans, 14 a lower aversion to bitter might be expected to increase ethanol consumption. However, we found little support for such a relationship.…”

“…5 Consistent with our finding of a difference between the two strains in sucrose intake, there is evidence that B6 mice have higher intakes than do 129 mice of several sweet compounds, including sucrose, 10 saccharin, 5,10-12 acesulfame, dulcin, 10 glycine, 13 d-phenylalanine, and l-glutamine. 12 A positive relationship between alcohol intake and sweet solution intake has also been found among other inbred strains of mice 5 and rats, 3,4 and within F 2 hybrids from ethanolpreferring and ethanol-nonpreferring rat strains. 3 Because these studies encompass a wide variety of nutritive and nonnutritive sweeteners, some of which are believed to have no postingestive effects, the results support the contention there is a genetically determined link between alcohol intake and sweet taste perception.…”

“…12 A positive relationship between alcohol intake and sweet solution intake has also been found among other inbred strains of mice 5 and rats, 3,4 and within F 2 hybrids from ethanolpreferring and ethanol-nonpreferring rat strains. 3 Because these studies encompass a wide variety of nutritive and nonnutritive sweeteners, some of which are believed to have no postingestive effects, the results support the contention there is a genetically determined link between alcohol intake and sweet taste perception.…”

“…A sweet component to alcohol taste has been demonstrated in rats, 2 which is consistent with several studies showing that the proclivity to drink alcohol is associated with elevated sweet preferences. [3][4][5] However, alcohol intake is also associated with reduced NaCI preferences, 4,6 even though it is not considered salty, and is unrelated to ingestion of bitter solutions 4 despite being bitter. 2 In addition to its gustatory properties, alcohol activates the olfactory and trigeminal (irritation/ burn) systems, 7 but there is no work to determine whether these are related to differences in intake.…”

Tryptophan metabolism in alcoholism

“…In the case of the mouse, the C57BL/6J strain has been shown to be the most alcohol-preferring of all mouse strains (McLearn & Rogers, 1959;Yoshimoto et al 1985;Yoshimoto & Komura, 1987), whereas, in the rat, a number of lines are known to prefer alcohol to water, namely the Finnish AA (Kiianmaa et al 1991), the Chilean UChB (Mardones & Segovia-Requelme, 1983), the Maudsley Reactive MRA (Satinder, 1972;Adams et al 1991), the Fawn-Hooded (Rezvani et al 1990;Overstreet et al 1993), the Indiana P ) and the Sardinian sP (Colombo, 1997), in comparison with their non-preferring counterparts (namely ANA, UchA, Maudsley Non-Reactive NMRA, Sprague-Dawley, and Wistar NP and sNP respectively). An interesting aspect of Trp metabolism in relation to alcohol preference is the low central 5-HT concentration in a number of the above animal models, including the C57BL/6J mouse (Badawy & Evans, 1976c;Yoshimoto et al 1985;Yoshimoto & Komura, 1987), Fawn-Hooded (Rezvani et al 1990), P , the Maudsley Reactive (Broadhurst, 1975) and sP (Devoto et al 1998) rat lines.…”