Journal of Neuroscience, Vol 1, 519-526, Copyright © 1981 by Society for Neuroscience
Cellular localization of 2-[3H]deoxy-D-glucose from paraffin-embedded brains
D Durham, TA Woolsey and L Kruger
Results of experiments in which regional neuronal activity is revealed by a
2-[3H]deoxy-D-glucose (3H-2-DG)-paraffin section-emulsion autoradiography
method are described. The trigeminal pathway of freely behaving mice was
activated differentially by selective patterns of whisker removal. One hour
after injection of concentrated 3H-2-DG, the animals were perfused
systemically with a periodate/lysine/paraformaldehyde mixture (McLean, I.
W., and P. K. Nakane (1974) J. Histochem. Cytochem. 22: 1077-1083), the
brains were embedded in paraffin, and serial sections were taken and coated
with emulsion for autoradiography. Diffusion of the isotope out of the
tissue was assessed visually and by liquid scintillation counting. While
substantial loss of 3H isotope into the embedding fluids (about 95%) was
found, the scintillation counts and the autoradiograms showed good fixation
of the isotope in situ, no evidence of isotope movement into the emulsion,
and no gradients of diffusion in the sectioned material. Patterns of
regional labeling were similar to those reported from brains prepared by
conventional 2-[14C]deoxy-D-glucose (14C-2-DG) autoradiography; for
instance, auditory and vestibular pathways in the brainstem were heavily
and specifically labeled. Trigeminal structures associated with the intact
(stimulated) whiskers were labeled relatively heavily, indicating that
label uptake is specific with respect to neuronal activity. In the cortex,
the patterns of label corresponded directly and precisely to those barrels
known to receive inputs from the intact whiskers. Distribution of silver
grains in the cortex and in the brainstem was correlated directly with
neuronal profiles, including processes, some of which were identified by
means of a Nissl counterstain. Clearly, this approach offers considerable
technical advantages, in particular, the ease with which the histological
material is prepared. The resolution of the autoradiograms and the quality
of the histology are excellent.