title: Weaker synaptic inhibition in CA1 region of ventral compared to dorsal rat hippocampal slices.
abstract: Extracellular and intracellular recordings were made from slices taken from the dorsal (DH) and ventral (VH) part of rat hippocampus. Using paired-pulse stimulation of Schaffer collaterals, at different interpulse intervals (IPIs), and records of the population spike (PS) we found that the strength and duration of paired-pulse inhibition was much weaker in VH compared to DH slices: at the IPI of 10 ms the decrease of PS in VH (40%) was significantly smaller compared to that in DH slices (76%), while at 20 ms the decrease of PS in DH slices (60%) corresponded to facilitation in VH slices. Moreover, the amplitude and duration of intracellularly recorded fast inhibitory postsynaptic potentials (fast-IPSPs) were found significantly smaller in VH (5.2+/-0.6 mV, 54.8+/-5.8 ms) than in DH (11.2+/-1.1 mV, 105+/-10 ms) neurons. The smaller and shorter fast-IPSP recorded in VH neurons may at least in part explain the results in paired-pulse inhibition. The demonstrated weaker inhibition may underlie the higher propensity of the ventral hippocampus for epileptiform activity.
authors.affiliation: Department of Physiology, Medical School, University of Patras, 265 00 Patras, Greece. cepapath@med.upatras.gr
authors.forename: Costas
authors.initials: C
authors.lastname: Papatheodoropoulos
authors.forename: Eftihia
authors.initials: E
authors.lastname: Asprodini
authors.forename: Ioanna
authors.initials: I
authors.lastname: Nikita
authors.forename: Christina
authors.initials: C
authors.lastname: Koutsona
authors.forename: George
authors.initials: G
authors.lastname: Kostopoulos
mesh_terms: D000818:Animals; D004558:Electric Stimulation; D005071:Evoked Potentials / Q000187:drug effects / Q000502:physiology; D018691:Excitatory Amino Acid Antagonists / Q000494:pharmacology; D018756:GABA Antagonists / Q000494:pharmacology; D058788:GABA-B Receptor Antagonists; D006624:Hippocampus / Q000166:cytology / Q000187:drug effects / Q000502:physiology*; D066298:In Vitro Techniques; D008297:Male; D009433:Neural Inhibition / Q000187:drug effects / Q000502:physiology*; D009928:Organ Specificity / Q000502:physiology; D017966:Pyramidal Cells / Q000187:drug effects / Q000502:physiology; D051381:Rats; D017208:Rats, Wistar; D013569:Synapses / Q000187:drug effects / Q000502:physiology*; D009435:Synaptic Transmission / Q000187:drug effects / Q000502:physiology*
chemical_list: D018691:Excitatory Amino Acid Antagonists; D018756:GABA Antagonists; D058788:GABA-B Receptor Antagonists