GLUT1 AND GLUT3 GENE-EXPRESSION IN GERBIL BRAIN FOLLOWING BRIEF ISCHEMIA - AN IN-SITU HYBRIDIZATION STUDY

GLUT1 and GLUT3 mRNAs in normal and post-ischemic gerbil brains were e xamined qualitatively and semi-quantitatively using in situ hybridizat ion in conjunction with image analysis. Coronal brain sections at the level of the anterior hippocampus were prepared three hours, one day, and three days after animals were subjected to six min of ischemia. Th e sections were hybridized with vector- and PCR-generated RNA probes l abeled with S-35. Microscopic evaluation of hybridized brain sections coated with autoradiographic emulsion indicated that GLUT1 mRNA was as sociated with brain microvessels, choroid plexus, and some ependymal c ells. GLUT1 mRNA was not observed in neurons, except that one day foll owing ischemia, this mRNA was induced in neurons of the dentate gyrus. GLUT3 mRNA was detected only in neurons. Image analysis of film autor adiograms revealed that both the GLUT1 and GLUT3 messages increased fo llowing ischemia but returned nearly to control levels by day three. I n the CA1 region of the hippocampus the increase in GLUT3 mRNA was not statistically significant, and by day three the level had fallen sign ificantly below the control, coinciding with the degeneration of the C A1 neurons. Our results suggest that the brain possesses mechanisms fo r induction and up-regulation of glucose transporter gene expression.