title: Role of alpha7-nicotinic acetylcholine receptors in tetanic stimulation-induced gamma oscillations in rat hippocampal slices.
abstract: Hippocampal gamma oscillations, as a form of neuronal network synchronization, are speculated to be associated with learning, memory and attention. Nicotinic acetylcholine receptor alpha7 subtypes (alpha7-nAChRs) are highly expressed in hippocampal neurons and play important roles in modulating neuronal function, synaptic plasticity, learning and memory. However, little is known about the role of alpha7-nAChRs in hippocampal gamma oscillations. Here, we examined the effects of selective alpha7- and non-alpha7-nAChR antagonists on tetanic gamma oscillations in rat hippocampal slices. We found that brief tetanic stimulation-induced gamma oscillations (30-80 Hz) and pharmacological blockade of alpha7-nAChRs using the relatively selective alpha7-nAChR antagonists, methyllycaconitine (10 or 100 nM) or alpha-bungarotoxin (10 nM), significantly reduced the frequency spectrum power, the number of spikes, and burst duration of evoked gamma oscillations. Neither mecamylamine nor dihydro-beta-erythroidine, which are selective antagonists of non-alpha7-nAChRs, demonstrated significant effects on tetanic gamma oscillations. Nicotine exposure promotes hippocampal gamma oscillations in a methyllycaconitine-sensitive manner. It is concluded that alpha7-nAChRs in hippocampal slices play important roles in regulation of gamma oscillations, thus potentially helping to explain roles of nAChRs in cognitive functions such as learning, memory and attention.
authors.affiliation: Division of Neurology, Barrow Neurological Institute, St. Joseph's Hospital and Medical Center, Phoenix, AZ 85013-4496, USA.
authors.forename: Chuanzhe
authors.initials: C
authors.lastname: Song
authors.forename: Teresa A
authors.initials: TA
authors.lastname: Murray
authors.forename: Ryoichi
authors.initials: R
authors.lastname: Kimura
authors.forename: Makoto
authors.initials: M
authors.lastname: Wakui
authors.forename: Kevin
authors.initials: K
authors.lastname: Ellsworth
authors.forename: Sam P
authors.initials: SP
authors.lastname: Javedan
authors.forename: Syndia
authors.initials: S
authors.lastname: Marxer-Miller
authors.forename: Ronald J
authors.initials: RJ
authors.lastname: Lukas
authors.forename: Jie
authors.initials: J
authors.lastname: Wu
mesh_terms: D000157:Aconitine / Q000031:analogs & derivatives* / Q000494:pharmacology; D000818:Animals; D000831:Animals, Newborn; D001640:Bicuculline / Q000494:pharmacology; D001683:Biological Clocks / Q000187:drug effects / Q000502:physiology / Q000528:radiation effects*; D002038:Bungarotoxins / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D004307:Dose-Response Relationship, Radiation; D004558:Electric Stimulation / Q000379:methods*; D004594:Electrophysiology / Q000379:methods; D018756:GABA Antagonists / Q000494:pharmacology; D006624:Hippocampus / Q000166:cytology / Q000187:drug effects / Q000502:physiology* / Q000528:radiation effects*; D066298:In Vitro Techniques; D009538:Nicotine / Q000494:pharmacology; D018722:Nicotinic Agonists / Q000494:pharmacology; D018733:Nicotinic Antagonists / Q000494:pharmacology; D051381:Rats; D017208:Rats, Wistar; D011978:Receptors, Nicotinic / Q000502:physiology*; D013057:Spectrum Analysis; D013997:Time Factors; D064569:alpha7 Nicotinic Acetylcholine Receptor
chemical_list: D002038:Bungarotoxins; C579165:Chrna7 protein, rat; D018756:GABA Antagonists; D018722:Nicotinic Agonists; D018733:Nicotinic Antagonists; D011978:Receptors, Nicotinic; D064569:alpha7 Nicotinic Acetylcholine Receptor; C054634:methyllycaconitine; D009538:Nicotine; D000157:Aconitine; D001640:Bicuculline