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Effects of body temperature on the immobile response and brain glucose metabolism were examined in the forced swimming test in mice. The first experiment was performed to study behavior, after initial periods of vigorous activity, a characteristic immobile posture occurred when the water was 25 and 35∘C. However, several minutes after forced swimming at 25∘C, significantly decreased spontaneous motility occurred in a time-dependent manner, but no changes was observed at 35∘C. Our interpretation was that mechanisms of acquisition and retention of the forced swim-induced immobile response differed. Body temperature was also significantly decreased at 25∘C but not at 35∘C in the forced swimming test. This lowering of body temperature almost paralleled the immobile response. The second experiment was a biochemical study in which the uptake of [14C] 2-deoxy-d-glucose into the brain significantly decreased after forced swimming at 25∘C but did not change in the forced swim loaded mice when the water was 35∘C. These results suggested two types of immobile mechanisms in the forced swimming test: (1) an early phase acquisition of the immobile response which might be related to adaptive response and (2) a late phase to retain the immobile response which might be related to the decrease in brain glucose metabolism.

Antiserum raised against horseradish peroxidase (HRP) recognizes neural specific carbohydrate antigens in Drosophilaand other insects. The occurrence of the antigens in mammalian cells was investigated. Proteins were extracted from rat pheochromocytoma cells, PC12, and various tissue of rat and bovine origin, and further purified by successive chromatography with Con A-Sepharose and anti-HRP glycopeptide antibody-Sepharose. The proteins were separated by SDS-PAGE and subjected to immunoblot analysis of the antigens. When the Con A- and antibody-Sepharose bound fractions were examined, four glycoproteins with carbohydrate antigens recognized by anti-HRP antiserum were identified in all the tissue. They are low molecular weight glycoproteins that are not membrane-bound. We demonstrated that the carbohydrate antigens recognized by the anti-HRP antibodies are not confined to insects but are expressed on mammalian cells in several tissue.