Kindling does not induce persistent changes in fluorographic labeling patterns of benzodiazepine binding proteins in various rat brain regions

The GABAA receptor has been implicated in the mechanisms underlying the phenomenon of kindling. Photoaffinity labeling with 3H-flunitrazepam followed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis allows the fluorographic visualization of GABAA receptor proteins with benzodiazepine binding sites which presumably correspond to different alpha-subtypes. This method offers an opportunity to investigate whether up- or down-regulation of single benzodiazepine binding proteins occurs. In the present study, labeling patterns of benzodiazepine binding proteins were determined in 12 brains regions of amygdala-kindled rats (2 weeks after the last fully kindled seizure) and sham-operated controls. For most brain regions, labeling patterns were separately determined for the ipsi- and contralateral side. A comparison of the labeling patterns thus obtained revealed no persistent changes between kindled animals and controls in any of the brain regions, including amygdala, substantia nigra and hippocampus. Thus, we conclude that kindling does not induce fluorographically detectable changes in the expression patterns of the benzodiazepine binding proteins. The results confirm the existence of regional heterogeneity of benzodiazepine binding proteins and extend the findings to brain regions which had previously not been investigated.