Functional and molecular characterization of neuronal nicotinic ACh receptors in rat hippocampal interneurons

Abstract

Publisher Summary This chapter elucidates the molecular makeup of functional neuronal nicotinic acetylcholine receptors (nAChRs) in various regions of the brain and nervous system, particularly in the rat hippocampal interneurons. nAChRs are ligand-gated ion channels that are widely expressed in the central and peripheral nervous system, where they can mediate fast excitatory synaptic transmission. The subunit composition of nAChRs determines their functional properties. A variety of functional and molecular studies have suggested that the two major subtypes of nAChRs found in the hippocampus are composed of α7 (the majority of the α-bungarotoxin binding sites) and α4β2 (the high affinity nicotine binding sites) subunits. Intrinsic cholinergic interneurons are shown to pattern network activity via nAChRs in rat hippocampal slices, and nAChR activation increases theta activity in freely moving rabbits. Thus, the activation of nAChRs via cholinergic input activates inhibitory interneurons, which in turn contributes to the synchronization of the principal cell firing. These mechanisms help in understanding the link between the activation of these receptors and cognition.