Excitatory synaptic transmission in hippocampal area CA1 is enhanced then reduced as chronic epilepsy progresses

NEUROBIOLOGY OF DISEASE

卷:154

Article

Owen, Benjamin^1,2  Bichler, Edyta^1,3  Benveniste, Morris¹ 

[1] Morehouse Sch Med, Neurosci Inst, 720 Westview Dr Sw, Atlanta, GA 30310 USA

[2] Vanderbilt Univ, Med Ctr, 1211 Med Ctr Dr, Nashville, TN 37232 USA

[3] Emory Univ, Dept Physiol, Sch Med, Atlanta, GA 30322 USA

关键词: Epilepsy;    Aging;    Pilocarpine;    EPSCs;    mEPSCs;    Fiber volleys;    Status epilepticus;    Synaptic transmission;    Hippocampus;   

DOI  :  10.1016/j.nbd.2021.105343

来源: Elsevier

【 摘 要 】

This study examines changes in synaptic transmission with progression of the chronic epileptic state. Male Sprague-Dawley rats (P40-45) were injected with either saline or pilocarpine. In rats injected with pilocarpine, status epilepticus ensued. Hippocampal slices were cut 20-60 days or 80-110 days post-treatment. Evoked and miniature EPSCs (mEPSCs) were recorded from CA1 pyramidal neurons using whole-cell voltage-clamp. Fiber volleys were also recorded from stratum radiatum. Evoked EPSCs from the pilocarpine-treated cohort showed enhanced amplitudes 20-60 days post-treatment compared to the saline-treated cohort, whereas mEPSCs recorded from the same age group showed no change in event frequency and a slight but significant decrease in mEPSC amplitude distribution. In contrast, comparing evoked EPSCs and mEPSCs recorded 80-110 days after treatment indicated reduced amplitudes from pilocarpine-treated animals compared to controls. mEPSC interevent interval decreased. This could be explained by a partial depletion of the ready releasable pool of neurotransmitter vesicles in Schaffer collateral presynaptic terminals of the pilocarpine-treated rats. In both saline- and pilocarpine-treated cohorts, concomitant decreases in mEPSC amplitudes as time after treatment progressed suggest that age-related changes in CA1 circuitry may be partially responsible for changes in synaptic transmission that may influence the chronic epileptic state.