Hippocampal Interneuronal alpha 7 nAChRs Modulate Theta Oscillations in Freely Moving Mice

Cell Reports. 2020. Vol. 31. No. 10. Article 107740.

Gu Z., Smith K., Alexander G., Guerreiro I., Dudek S., Гуткин Б. С., Jensen P., Yakel J.

Muscarinic acetylcholine receptors (mAChRs) are critically involved in hippocampal theta generation, but much less is known about the role of nicotinic AChRs (nAChRs). Here we provide evidence that α7 nAChRs expressed on interneurons, particularly those in oriens lacunosum moleculare (OLM), also regulate hippocampal theta generation. Local hippocampal infusion of a selective α7 nAChR antagonist significantly reduces hippocampal theta power and impairs Y-maze spontaneous alternation performance in freely moving mice. By knocking out receptors in different neuronal subpopulations, we find that α7 nAChRs expressed in OLM interneurons regulate theta generation. Our in vitro slice studies indicate that α7 nAChR activation increases OLM neuron activity that, in turn, enhances pyramidal cell excitatory postsynaptic currents (EPSCs). Our study also suggests that mAChR activation promotes transient theta generation, while α7 nAChR activation facilitates future theta generation by similar stimulations, revealing a complex mechanism whereby cholinergic signaling modulates different aspects of hippocampal theta oscillations through different receptor subtypes.

Keywords: hippocampus, theta oscillations, alpha7 nicotinic acetylcholine receptor, oriens lacunosum moleculare interneuron

Publication based on the results of: Multidisciplinary investigation of neurocognitive brain processes using neurophysiological, behavioral and structural approaches (2020)