Peptidergic modulation of synaptic activity in the hippocampus

We present here results from studies of the physiological mechanisms of action of two neuropeptides widely used in clinical practice as nootropes and anxiolytics: Noopept, a peptide analog of piracetam and, Selank, a synthetic analog of the peptide tuftsin. Patch-clamp studies on hippocampal slices addressed the modulation of spontaneous inhibitory ion currents in pyramidal neurons on exposure to study neuropeptides. The main effect of both substances consisted of an increase in the frequency of spontaneous inhibitory postsynaptic currents (IPSC) in pyramidal cells of the radial layer of field CA1, evidently due to an increase in the discharge frequency of inhibitory interneurons terminating on these cells (demonstrated only for Noopept). The consequence of the increase in IPSC frequency in pyramidal neurons is strengthening of the inhibitory control of limbic structures by the hippocampus, which in turn appears to underlie the anxiolytic effects of both agents. The mechanisms of their nootropic actions will be addressed in future studies. © 2013 Springer Science+Business Media New York.