Autoradiographic analysis of benzodiazepine binding in entorhinal-kindled rat brains.

A quantitative autoradiographic analysis of binding to 'central' benzodiazepine ([3H]flunitrazepam) receptors was carried out in 95 brain areas from entorhinal-kindled and handled control rats. Animals were sacrificed either 24 h or 28 days after the last kindled seizure. A significant post-kindling change was observed in only one area, the fascia dentata, which showed an elevation of 31% at 24 h, but not at 28 days. This change, which appeared in both the dorsal and ventral divisions of the hippocampus, was largest in the suprapyramidal layer. These data confirm previous reports of transient post-kindling binding changes in the fascia dentata, and extend them by suggesting that the fascia dentata is the only site in the brain which shows altered benzodiazepine binding after kindling. These transient and circumscribed changes are unlikely to contribute significantly to the 'kindled state', although they may relate to the enhancement of inhibitory effects observed in fascia dentata after kindling.