title: Cholinergic modulation of synaptic transmission and plasticity in entorhinal cortex and hippocampus of the rat.
abstract: Effects of cholinergic agents on synaptic transmission and plasticity were examined in entorhinal cortex and hippocampus. Bath application of carbachol (0.25-0.75 microM) induced transient depression of field potential responses in all cases tested (24/24 in layer III of medial entorhinal cortex slices and 24/24 in CA1 of hippocampal slices; 11.0+/-1.9% and 7.8+/-2.5%, respectively) and long-lasting potentiation in some cases (4/24 in entorhinal cortex and 12/24 in hippocampus; 33.7+/-3.7% and 32.1+/-9.9%, respectively, in successful cases). Carbachol (0.5 microM) induced transient depression, but not long-lasting potentiation, of N-methyl-D-aspartate receptor-mediated responses in entorhinal cortex. At 5 microM, carbachol induced transient depression only (55. 9+/-4.7% in entorhinal cortex and 41.4+/-2.9% in hippocampus), which was blocked by atropine. Paired-pulse facilitation was not altered during carbachol-induced potentiation but enhanced during carbachol-induced depression. These results suggest that the underlying mechanisms of carbachol-induced depression and potentiation are decreased transmitter release and selective enhancement of non-N-methyl-D-aspartate receptor-mediated responses, respectively. Long-term potentiation could be induced in the presence of 10 microM atropine by theta burst stimulation. The magnitude was significantly lower (15.2+/-5.2%, n=9) compared with control (37.2+/-6.1%, n=8) in entorhinal cortex, however. These results demonstrate similar, but not identical, cholinergic modulation of synaptic transmission and plasticity in entorhinal cortex and hippocampus.
authors.affiliation: Neuroscience Laboratory, Institute for Medical Sciences, Ajou University School of Medicine, 442-721, Suwon, South Korea.
authors.forename: S H
authors.initials: SH
authors.lastname: Yun
authors.forename: M Y
authors.initials: MY
authors.lastname: Cheong
authors.forename: I
authors.initials: I
authors.lastname: Mook-Jung
authors.forename: K
authors.initials: K
authors.lastname: Huh
authors.forename: C
authors.initials: C
authors.lastname: Lee
authors.forename: M W
authors.initials: MW
authors.lastname: Jung
mesh_terms: D018750:6-Cyano-7-nitroquinoxaline-2,3-dione / Q000494:pharmacology; D000818:Animals; D001285:Atropine / Q000494:pharmacology; D002217:Carbachol / Q000494:pharmacology*; D004558:Electric Stimulation; D018728:Entorhinal Cortex / Q000187:drug effects / Q000502:physiology*; D005071:Evoked Potentials / Q000187:drug effects; D006624:Hippocampus / Q000187:drug effects / Q000502:physiology*; D066298:In Vitro Techniques; D017774:Long-Term Potentiation / Q000187:drug effects / Q000502:physiology; D008274:Magnesium / Q000494:pharmacology; D008297:Male; D009473:Neuronal Plasticity / Q000187:drug effects / Q000502:physiology*; D017966:Pyramidal Cells / Q000187:drug effects / Q000502:physiology; D051381:Rats; D017207:Rats, Sprague-Dawley; D016194:Receptors, N-Methyl-D-Aspartate / Q000502:physiology; D009435:Synaptic Transmission / Q000187:drug effects / Q000502:physiology*
chemical_list: D016194:Receptors, N-Methyl-D-Aspartate; D018750:6-Cyano-7-nitroquinoxaline-2,3-dione; D001285:Atropine; D002217:Carbachol; D008274:Magnesium