Role of alpha7-nicotinic acetylcholine receptors in tetanic stimulation-induced gamma oscillations in rat hippocampal slices.
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.
Song
Chuanzhe
C
Division of Neurology, Barrow Neurological Institute, St. Joseph's Hospital and Medical Center, Phoenix, AZ 85013-4496, USA.
Murray
Teresa A
TA
Kimura
Ryoichi
R
Wakui
Makoto
M
Ellsworth
Kevin
K
Javedan
Sam P
SP
Marxer-Miller
Syndia
S
Lukas
Ronald J
RJ
Wu
Jie
J
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
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