Long-term change in synaptic transmission in CA3 circuits followed by spontaneous rhythmic activity in rat hippocampal slices

Content Provider	Semantic Scholar
Author	Nakashima, Koushi Hayashi, Hatsuo Shimizu, Osamu Ishizuka, Satoru
Copyright Year	2001
Abstract	The relevance of long-term potentiation (LTP) at excitatory synapses in CA3 circuits to generation of spontaneous epileptiform bursts in CA3 was investigated using rat hippocampal slices. CA3 pyramidal cells were antidromically stimulated through Schaffer collaterals. Evoked field potentials were extracellularly recorded from the stratum pyramidale and the stratum radiatum in CA3. Therefore, field potentials reflecting recurrent excitatory post-synaptic potentials (EPSPs) and inhibitory post-synaptic potentials (IPSPs) were positive at the stratum pyramidale and negative at the stratum radiatum. First, we tested how the amplitude of the evoked field potentials depends on a gamma-aminobutyric acid (GABA(A)) antagonist. Both of the positive and negative field potential peaks reduced in the medium containing penicillin (2 mM) or bicuculline (20 microM). This suggests that unmasked EPSPs due to suppression of IPSPs do not result in an increase in the evoked potentials. Second, CA3 pyramidal cells were antidromically stimulated by tetanic stimulation of Schaffer collaterals in order to induce LTP at synapses in CA3 circuits. Both of the positive and negative field potentials increased, suggesting that recurrent EPSPs were enhanced by tetanic stimulation. Induction of LTP at recurrent excitatory synapses was followed by spontaneous epileptiform bursts which persisted throughout experiments (approximately 1.5 h), while LTP of afferent synaptic potential evoked by hilar test stimulation was not induced. These results suggest that LTP at the afferent synapses is not necessary to spontaneous epileptiform bursts in CA3, but LTP at excitatory synapses between CA3 pyramidal cells contribute to spontaneous epileptiform bursts.
Starting Page	325
Ending Page	336
Page Count	12
File Format	PDF HTM / HTML
DOI	10.1016/S0168-0102(01)00244-9
PubMed reference number	11463478
Journal	Medline
Volume Number	40
Alternate Webpage(s)	https://api.elsevier.com/content/article/pii/S0168010201002449
Alternate Webpage(s)	https://www.sciencedirect.com/science/article/pii/S0168010201002449?dgcid=api_sd_search-api-endpoint
Alternate Webpage(s)	https://doi.org/10.1016/S0168-0102%2801%2900244-9
Journal	Neuroscience Research
Language	English
Access Restriction	Open
Content Type	Text
Resource Type	Article