GABAB antagonists diminish the inhibitory gating of auditory response in the rat hippocampus

Auditory evoked responses recorded from the CA3 region of the rat hippocampus show diminished response to repeated stimuli, suggesting the activity of an inhibitory gating mechanism. The effects on this putative gating mechanism of two GABAB receptor antagonists, CGP35348 and CGP46381, were characterized in a conditioning testing paradigm. Both compounds, administered intracerebroventricularly, antagonized the suppression of response to the test stimulus. The results are consistent with the hypothesis that this inhibitory gating of response involves GABAB receptors, which may control the release of glutamate from excitatory pathways in the hippocampus.

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