The effect of carbenoxolone on hippocampal formation theta rhythm in rats: In vitro and in vivo approaches

The role of gap junction (GJ) coupling in the generation of hippocampal formation theta rhythm was investigated in vitro, with use of brain slices, and in vivo, with use of urethane anesthetized rats. Carbenoxolone, the succinyl ester of glycyrrhetinic acid, and GJ blocker reversibly abolished hippocampal formation theta rhythm recorded in slice preparations and urethane anesthetized rats. The present study yielded novel data which demonstrated that the pattern of delay in blockage of theta rhythm after carbenoxolone treatment, and the pattern of theta recovery after administration of this agent, require a specific time period (2–3 h for delay and 8–12 h for recovery), one that can be demonstrated using different experimental protocols.