Benzodiazepine Receptor Binding Following Amygdala-Kindled Convulsions: Differing Results in Washed and Unwashed Brain Membranes

The binding of 3H]flunitrazepam and 3H]RO5-4864 was measured in unwashed brain homogenates and in extensively washed brain membranes from amygdala-kindled and "yoked" control rats sacrificed 2 weeks following the sixth stage 5 convulsion. In unwashed homogenates, 3H]flunitrazepam binding was reduced in both the hypothalamus and ipsilateral right cortex of kindled rats (unchanged in other areas). In washed brain membranes, 3H]flunitrazepam binding was unaltered in these regions; it was bilaterally elevated, however, in both the amygdala and hippocampus (unchanged in other areas). In washed membranes, the in vitro addition of gamma-aminobutyric acid enhanced 3H]flunitrazepam binding to a similar extent in kindled and control membranes. These data indicate that the type of benzodiazepine binding abnormality observed after kindling depends on the type of tissue preparation employed in the assay procedure.