PNU 120596 is a type II positive allosteric modulator of α7 neuronal nicotinic acetylcholine receptor (AChR) located on the somatodendritic membrane of hippocampal interneurons. This modulator increases the frequency of acetylcholine-evoked GABAergic postsynaptic currents in pyramidal neurons, which can be suppressed by TTX. In addition, studies show that PNU 120596 increases the average time the channel of AChR is open, but does not have any effect on the selectivity of ions flowing through the channel. Furthermore, PNU 120596 has little effect on α4β2, α3β4 and α9α10 receptors. Alternate studies indicate that PNU 120596 increases the effects of choline on native α7-containing AChRs activating these receptors, thus producing single ion channel openings which result in an influx of calcium ions, that can be inhibited with the addition of methyllycaconitine