Aniracetam has proportionately smaller effects on synapses expressing long-term potentiation: Evidence that receptor changes subserve LTP

The effects of the nootropic compound aniracetam on synaptic responses expressing long-term potentiation (LTP) were compared with those on control responses in field CA1 of hippocampal slices. The drug produced smaller percentage increases in the amplitude of potentiated, as opposed to control, inputs. Field EPSPs enhanced by the paired-pulse facilitation paradigm, however, were affected to the same degree as control responses. Since aniracetam is known to selectively augment the conductance of AMPA receptor channels, these results indicate that LTP expression is likely to involve modifications of postsynaptic receptors.