No abstract

Effects of viscosity upon licking were studied by providing rats with thick and thin .4% saccharin solutions in separate 1-h sessions. Volumetric intake{lick was greater for the thin than for the thick solution and was the only measure affected by viscosity. As the session progressed, the two solutions caused (1) comparable satiation effects, as evidenced by comparable decreases in several indices of the average rate of ingestion; (2) comparable decreases in the average duration of the lick; and (3) no reliable change in the average volumetric intake of the lick. The results were related to earlier comparisons of liquid food and saccharin and indicated that the differences produced by the latter solutions are not fully attributable to their differential viscosity.

No abstract

The drinking response to hypertonic loads can be depressed by frontal pole and/or olfactory bulb lesions. In order to evaluate the role of each of these structures, 36 rats were mechanically or electrolytically lesioned in the olfactory bulbs or frontal poles. Following hypertonic loading by IP injection of NaCI, animals with olfactory lesions always drank like normal control animals, while animals with frontal lesions showed depressed, normal, or elevated drinking responses. These results were interpreted in relation to the known physiology of the hypothalamus and connections between hypothalamus and frontal poles. *NaCI injection was 2.0% or body weight in normal, frontally lesioned, and olfactory lesioned animals.