The actions of 2-hydroxy-saclofen at presynaptic GABAB receptors in the rat hippocampus.

The actions of 2-hydroxy-saclofen (2-OH-S), a recently developed analog of baclofen, were studied at presynaptic GABAB receptors in the rat hippocampal slice. Baclofen (0.5-20 microM) reduces the amplitude of excitatory postsynaptic potentials (EPSPs) recorded from hippocampal CA1 pyramidal neurons. In the presence of 200-500 microM 2-OH-S, the synaptic depressant action of baclofen is significantly reduced. These data show that 2-OH-S is an effective antagonist at presynaptic GABAB receptors on excitatory terminals in the hippocampus.