Experimental Brain Research

, Volume 106, Issue 2, pp 248–256

Long-term potentiation deficits and excitability changes following traumatic brain injury

Authors

  • Thomas M. Reeves
    • Department of AnatomyMedical College of Virginia
  • Bruce G. Lyeth
    • Division of NeurosurgeryMedical College of Virginia
  • John T. Povlishock
    • Department of AnatomyMedical College of Virginia
Research Article

DOI: 10.1007/BF00241120

Cite this article as:
Reeves, T.M., Lyeth, B.G. & Povlishock, J.T. Exp Brain Res (1995) 106: 248. doi:10.1007/BF00241120

Abstract

The effects of traumatic brain injury (TBI) on hippocampal long-term potentiation (LTP) and cellular excitability were assessed at postinjury days 2, 7, and 15. TBI was induced using a well-characterized central fluid-percussion model. LTP of the Schaffer collateral/commissural system was assessed in vivo in urethane-anesthetized rats. Significant LTP of the population excitatory postsynaptic potential (EPSP) slope was found only in controls, and no recovery to control levels was observed for any postinjury time point. Four measurement parameters reflecting pyramidal cell discharges (population spike) indicated that TBI significantly increased cellular excitability at postinjury day 2: (1) pretetanus baseline recording showed that TBI reduced population spike threshold and latency; (2) tetanic stimulation (400 Hz) increased population spike amplitudes to a greater degree in injured animals than in control animals; (3) tetanus-induced population spike latency shifts were greater in injured cases; and (4) tetanic stimulation elevated EPSP to spike ratios (E-S potentiation) to a greater degree in injured animals. These parameters returned to control levels, as measured on postinjury days 7 and 15. These results suggest that TBI-induced excitability changes persist at least through 2 days postinjury and involve a differential impairment of mechanisms subserving LTP of synaptic efficacy and mechanisms related to action potential generation

Key words

Long-term potentiationTraumatic brain injuryExcitabilityHippocampusRat

Copyright information

© Springer-Verlag 1995