Facilitation of glutamatergic synaptic transmission in hippocampal CA1 area of rats with traumatic brain injury

Experimental Mild Traumatic Brain Injury Induces Functional Alteration of the Developing Hippocampus

“…In our studies, as indicated by a leftward-shift of the CPD for injured cultures, paired-pulse ratios were significantly decreased with some PPF becoming PPD in CA1 and CA3 at 1 DPI. Previous studies have found that paired-pulse ratios in the CA1 region could be either suppressed (Cao et al 2006) or elevated (Reeves et al 2000) after experimental TBI with changes persistent for a week post injury (Reeves et al 2000). The difference between previous findings and our results could be due to several possible reasons.…”

Mild Hypothermia Prevents Post-Traumatic Hyperactivity of Excitatory Synapses in Rat Hippocampal CA1 Pyramidal Neurons

“…Previous studies have shown that FPI did not alter the neuronal activity of presynaptic neurons in the hippocampal CA1 area of horizontal brain slices [22]. Furthermore, FPI markedly enhanced the excitatory postsynaptic potential (EPSP) following FPI in the hippocampal CA1 area [21]. Thus the enhanced propagation of optical activity in hippocampal CA1 neurons is mainly due to the enhancement of excitatory synaptic activity.…”

“…It is possible that the post-traumatic hyperexcitability is due to pathologic inhibition of γ-aminobutyric acid (GABA)-neurons, because GABA-neuron loss lowers the action potential threshold for developing self-sustained seizure activity 1-12 weeks post-injury [10,11,13]. However, a previous study showed that the post-traumatic enhancement of excitatory synapses was not directly related to the disinhibition of GABAergic neurotransmission in the hippocampal CA1 area [21]. Further, FPI caused no considerable change in gross structure in the lateral hippocampal CA1 neurons lying 5 mm deep relative to the injured cerebral cortex [19,20,22].…”

“…Animals were maintained on a 12/12 (light-dark) cycle and given food ad libitum. FPI of the rat brain was induced by the methods described previously [4,5,[19][20][21]23]. Briefly, adult male Wistar rats (250-300 g) were anesthetized by intraperitoneal (i.p.)…”

“…Lowering brain temperature produces behavioral protection after experimental TBI [17,18]. Recently, we showed a marked enhancement of neuronal excitability in the lateral hippocampus 1 week after administration of FPI to the cerebral cortex [19][20][21][22]. The aim of the present study was to examine whether very mild hypothermia (35°C) prevents the FPI-induced enhancement of excitatory synaptic transmission in the hippocampal CA1 area.…”