Regional Distribution of High‐Affinity γ‐[3H] Hydroxybutyrate Binding Sites as Determined by Quantitative Autoradiography

Publisher Website
Google Scholar
Abstract
The distribution of high-affinity binding sites for .gamma.-[3H]hydroxybutyrate in coronal sections of rat brain was studied by quantitative autoradiographic techniques. Binding sites for this naturally occurring substance, which may possibly have a neurotransmitter role, are concentrated in some restricted areas of the brain, particularly in the limbic system. The hippocampus (especially field CA1 of Ammon''s horn, at 292 fmol/mg of tissue), septum (72 fmol/mg of tissue), and cortex (frontal, 113 fmol/mg of tissue; parietal, 103 fmol/mg of tissue; cingulate, 114 fmol/mg of tissue; and entorhinal, 134 fmol/mg of tissue) show pronounced labeling with .gamma.-[3H]hydroxybutyrate. Binding is much lower in caudate-putamen (50 fmol/mg of tissue), thalamus, and hypothalamus. Cauda parts of the brain (Cerebellum, pons, and medulla) are practically devoid of binding sites. These results strongly support a functional role of endogenous .gamma.-hydroxybutyrate in particularly restricted areas of the rat brain.