Comparative extracellular current flow at dendrites and soma of dentate granule cells during long-term potentiation.
In the study of long-term potentiation (LTP) in the dentate gyrus, the magnitude of the initial slope of the evoked synaptic potential (ESP) in the region of the granule cell layer, is commonly used as a measure of synaptic efficacy at the site of the perforant path (PP) input. To investigate the viability of this assumption, in rats anesthetized with either chloropent or urethane, LTP was induced by tetanic stimulation of the PP and ESPs were measured simultaneously at both the soma and dendritic site of the PP input. Following LTP, the two responses were decoupled, the somal response being greater than the dendritic in rats anesthetized with chloropent, the opposite being true in urethanized animals. We conclude that in investigating changes in synaptic efficacy following LTP, measurements should be taken at the site of the PP input.
Pavlides
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Rockefeller University, New York, NY 10021.
Greenstein
Y J
YJ
Winson
J
J
D000200:Action Potentials / Q000187:drug effects; D000758:Anesthesia; D000818:Animals; D002697:Chloral Hydrate; D003712:Dendrites / Q000187:drug effects / Q000502:physiology*; D004338:Drug Combinations; D004558:Electric Stimulation; D006624:Hippocampus / Q000166:cytology / Q000187:drug effects / Q000502:physiology*; D008278:Magnesium Sulfate; D008297:Male; D010424:Pentobarbital; D051381:Rats; D011919:Rats, Inbred Strains; D014520:Urethane
D004338:Drug Combinations; C034864:chloropent; D014520:Urethane; D002697:Chloral Hydrate; D008278:Magnesium Sulfate; D010424:Pentobarbital