Deletion of Glucose Transporter GLUT8 in Mice Increases Locomotor Activity

Transport of glucose into neuronal cells is predominantly mediated by the glucose transporters GLUT1 and GLUT3. In addition, GLUT8 is expressed in some regions of the brain. By in situ hybridization we detected GLUT8-mRNA in hippocampus, thalamus, and cortex. However, its cellular and physiological function is still unknown. Thus, GLUT8 knockout (Slc2a8−/−) mice were used for a screening approach in the modified hole board (mHB) behavioral test to analyze the role of GLUT8 in the central nervous system. Slc2a8−/− mice showed increased mean velocity, total distance traveled and performed more turns in the mHB test. This hyperactivity of Slc2a8−/− mice was confirmed by monitoring locomotor activity in the home cage and voluntary activity in a running wheel. In addition, Slc2a8−/− mice showed increased arousal as indicated by elevated defecation, reduced latency to the first defecation and a tendency to altered grooming. Furthermore, the mHB test gave evidence that Slc2a8−/− mice exhibit a reduced risk assessment because they performed less rearings in an unprotected area and showed significantly reduced latency to stretched body posture. Our data suggest that behavioral alterations of Slc2a8−/− mice are due to dysfunctions in neuronal processes presumably as a consequence of defects in the glucose metabolism

Characterizing the scent and chemical composition of Panthera leo marking fluid using solid-phase microextraction and multidimensional gas chromatography–mass spectrometry-olfactometry

Lions (Panthera leo) use chemical signaling to indicate health, reproductive status, and territorial ownership. To date, no study has reported on both scent and composition of marking fluid (MF) from P. leo. The objectives of this study were to: 1) develop a novel method for simultaneous chemical and scent identification of lion MF in its totality (urine + MF), 2) identify characteristic odorants responsible for the overall scent of MF as perceived by human panelists, and 3) compare the existing library of known odorous compounds characterized as eliciting behaviors in animals in order to understand potential functionality in lion behavior. Solid-phase microextraction and simultaneous chemical-sensory analyses with multidimensional gas-chromatography-mass spectrometry-olfactometry improved separating, isolating, and identifying mixed (MF, urine) compounds versus solvent-based extraction and chemical analyses. 2,5-Dimethylpyrazine, 4-methylphenol, and 3-methylcyclopentanone were isolated and identified as the compounds responsible for the characteristic odor of lion MF. Twenty-eight volatile organic compounds (VOCs) emitted from MF were identified, adding a new list of compounds previously unidentified in lion urine. New chemicals were identified in nine compound groups: ketones, aldehydes, amines, alcohols, aromatics, sulfur-containing compounds, phenyls, phenols, and volatile fatty acids. Twenty-three VOCs are known semiochemicals that are implicated in attraction, reproduction, and alarm-signaling behaviors in other species