title: Cholinergic induction of oscillations in the hippocampal slice in the slow (0.5-2 Hz), theta (5-12 Hz), and gamma (35-70 Hz) bands.
abstract: Carbachol, a muscarinic receptor agonist, produced three distinct spontaneous oscillations in the CA3 region of rat hippocampal slices. Carbachol concentrations in the 4-13 microM range produced regular synchronized CA3 discharges at 0.5-2 Hz (carbachol-delta). Higher concentrations (13-60 microM) produced short episodes of 5-10 Hz (carbachol-theta) oscillations separated by nonsynchronous activity. Concentrations of carbachol ranging from 8-25 microM also produced irregular episodes of high-frequency discharges (carbachol-gamma, 35-70 Hz), in isolation or mixed with carbachol-theta and carbachol-delta. At carbachol concentrations sufficient to induce carbachol-theta, low concentrations of APV reversibly transformed carbachol-theta into carbachol-delta. Higher concentrations of D,L-2-amino-5-phosphonopentanoic acid (APV) reversibly and completely blocked carbachol-theta. A systematic study of the effects of carbachol shows that the frequency of spontaneous oscillations depended nonlinearly on the level of muscarinic activation. Field and intracellular recordings from CA1 and CA3 pyramidal cells and interneurons during carbachol-induced rhythms revealed that the hippocampal circuitry preserved in the slice was capable of spontaneous activity over the range of frequencies observed in vivo and suggests that the presence of these rhythms could be under neuromodulatory control.
authors.affiliation: Computational Neurobiology Laboratory, Howard Hughes Medical Institute, Salk Institute for Biological Studies, La Jolla, California 92037, USA. fellous@salk.edu
authors.forename: J M
authors.initials: JM
authors.lastname: Fellous
authors.forename: T J
authors.initials: TJ
authors.lastname: Sejnowski
mesh_terms: D000109:Acetylcholine / Q000502:physiology; D000818:Animals; D002217:Carbachol / Q000494:pharmacology*; D018679:Cholinergic Agonists / Q000494:pharmacology*; D003700:Delta Rhythm / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D006624:Hippocampus / Q000166:cytology / Q000187:drug effects / Q000502:physiology*; D007395:Interneurons / Q000502:physiology; D009433:Neural Inhibition / Q000187:drug effects / Q000502:physiology; D009924:Organ Culture Techniques; D010507:Periodicity; D017966:Pyramidal Cells / Q000502:physiology; D051381:Rats; D017207:Rats, Sprague-Dawley; D011930:Reaction Time / Q000187:drug effects / Q000502:physiology; D013826:Theta Rhythm / Q000187:drug effects*
chemical_list: D018679:Cholinergic Agonists; D002217:Carbachol; D000109:Acetylcholine