title: Carbachol-induced network oscillations in an in vitro limbic system brain slice.
abstract: We employed simultaneous field potential recordings from CA3, subiculum and entorhinal cortex in an in vitro brain slice preparation to understand the involvement of these limbic areas in the generation of the field potential oscillations that are induced by bath application of the muscarinic receptor agonist carbachol. Regularly spaced oscillations that mainly presented at theta frequency range (5-12Hz) occurred synchronously in all three structures in the presence of carbachol. These oscillations, which disappeared when slices were perfused with pirenzepine or with glutamatergic receptor antagonists, were categorized as short (<4s) and long (>4s) with short events oscillating at higher frequencies than long events. Field oscillations were highly synchronized between regions and latency analysis revealed that they often initiated in the entorhinal cortex later than in the other two structures. Blocking GABAAreceptors modified the activity patterns of both short and long oscillations and decreased their coherence in the theta frequency range. Finally, blocking KCC2 activity disclosed a pattern of recurrent short oscillations. Our results suggest that in the presence of carbachol both subiculum and CA3 most often drive theta generators in the entorhinal cortex and that these oscillations are influenced but not abolished by altering GABAAreceptor signaling.
authors.affiliation: Montreal Neurological Institute and Department of Neurology & Neurosurgery, McGill University, 3801 University Street, Montréal, PQ H3A 2B4, Canada.
authors.forename: Maxime
authors.initials: M
authors.lastname: Lévesque
authors.affiliation: Division of Pharmacology, Department of Neuroscience, Reproductive Science and Dentistry, School of Medicine, "Federico II" University of Naples, Naples, Italy.
authors.forename: Mauro
authors.initials: M
authors.lastname: Cataldi
authors.affiliation: Montreal Neurological Institute and Department of Neurology & Neurosurgery, McGill University, 3801 University Street, Montréal, PQ H3A 2B4, Canada.
authors.forename: Li-Yuan
authors.initials: LY
authors.lastname: Chen
authors.affiliation: Montreal Neurological Institute and Department of Neurology & Neurosurgery, McGill University, 3801 University Street, Montréal, PQ H3A 2B4, Canada.
authors.forename: Shabnam
authors.initials: S
authors.lastname: Hamidi
authors.affiliation: Montreal Neurological Institute and Department of Neurology & Neurosurgery, McGill University, 3801 University Street, Montréal, PQ H3A 2B4, Canada. Electronic address: massimo.avoli@mcgill.ca.
authors.forename: Massimo
authors.initials: M
authors.lastname: Avoli
mesh_terms: D000818:Animals; D056654:CA3 Region, Hippocampal / Q000187:drug effects*; D002217:Carbachol / Q000494:pharmacology*; D018679:Cholinergic Agonists / Q000494:pharmacology*; D018728:Entorhinal Cortex / Q000187:drug effects*; D006624:Hippocampus / Q000187:drug effects*; D008297:Male; D018727:Muscarinic Antagonists / Q000494:pharmacology; D009415:Nerve Net / Q000187:drug effects*; D009474:Neurons / Q000187:drug effects; D010890:Pirenzepine / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D013826:Theta Rhythm / Q000187:drug effects
chemical_list: D018679:Cholinergic Agonists; D018727:Muscarinic Antagonists; D010890:Pirenzepine; D002217:Carbachol
keywords: GABA(A) receptor; KCC2; carbachol; picrotoxin; theta oscillations