The influence of the neurohumor serotonin on hibernation in the golden-mantled ground squirrel, Citellus lateralis

Abstract

1. 1. The neurohumor, serotonin, has been shown to be functionally involved in hibernation in the ground squirrel Citellus lateralis. Using the serotonin synthesis inhibitor, para-chlorophenyl amine, hibernation was temporarily abolished. 2. 2. Lesion of 30 per cent of the median raphe nucleus of the midbrain, which is a major locus of serotonin synthesis, caused disruption of hibernation when compared to controls lesioned in the lateral tegmentum. 3. 3. Whole brain serotonin levels decrease significantly during entrance into hibernation. 4. 4. In C. tereticaudus there is a significant difference in whole brain serotonin levels between males and females, which fits the fact that the sexes do hibernate in a different behavioral pattern. 5. 5. A correlation between ability to hibernate and whole brain serotonin levels is shown in three species of ground squirrel. © 1971.