Costas Papatheodoropoulos

George Kostopoulos9
Evangelos Sotiriou3
9George Kostopoulos
3Evangelos Sotiriou
3Theodoros Petrides
3Christos Moschovos
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This study demonstrates that transverse slices taken from the ventral hippocampus of adult rats perfused with a medium of normal ionic composition sustain spontaneous periodic field potentials due to the synchronous activity of a population of neurons. This ventral hippocampus spontaneous synchronous activity (VHSSA) in CA1 stratum pyramidale consisted of(More)
Recent data demonstrate weaker gamma-aminobutyric acid (GABA)-ergic inhibition in ventral (VH) compared with dorsal (DH) hippocampus. Therefore, we examined possible differences regarding the GABAA receptors between VH and DH as follows: 1) the expression of the GABAA receptor subunits (alpha1/2/4/5, beta1/2/3, gamma2, delta) mRNA and protein and 2) the(More)
Evidence accumulating during the past few years points to a significant role of matrix metalloproteinase 9 (MMP9) enzymatic activity in synaptic plasticity and cognitive processes. We have previously demonstrated that MMP9 is involved in receptor-mediated α-secretase-like cleavage of APP in vitro, resulting in increased secretion of sAPPα, the soluble(More)
High-frequency oscillations (HFOs or ripples, >or=100 Hz) appear to be important expressions of cortical circuits, characterizing physiological and pathological functional states. Synaptic and non-synaptic mechanisms are involved in their generation. This study shows that spontaneous N-methyl-D-aspartate receptor (NMDAR) mediated potentials, recorded in(More)
The present study shows that adult rat transverse slices from the ventral hippocampus perfused with standard medium persistently generate spontaneous synchronous field potentials. In CA1 st. pyramidale this regular ventral hippocampus spontaneous synchronous activity (VHSSA) was positive with mean amplitude 0.18 +/- 0.02 mV (n=80 slices) and occurred every(More)
BACKGROUND AND PURPOSE Hippocampus-dependent memory involves the activity of sharp wave ripples (SWRs), which are thought to participate in the process of memory consolidation. The hippocampus contains high levels of endogenous opioids and of μ-opioid receptors (MORs). Here, we have assessed the role of MOR agonists in the modulation of SWRs. EXPERIMENTAL(More)
Extracellular and intracellular recordings were made from slices taken from the dorsal (DH) and ventral (VH) part of rat hippocampus. Using paired-pulse stimulation of Schaffer collaterals, at different interpulse intervals (IPIs), and records of the population spike (PS) we found that the strength and duration of paired-pulse inhibition was much weaker in(More)
Although adenosine is widely assumed to be an endogenous anticonvulsant its role in epileptogenesis is still contradictory. Using slices from the dorsal (DH) and the vental (VH) rat hippocampus and extracellular recordings from the CA3 field we aimed to determine the effects of endogenous adenosine on the expression and long-term maintenance of epileptiform(More)
Sharp waves and ripples (SWRs) are a basic endogenous network activity of the hippocampus. Growing evidence from in vivo studies suggests that this activity plays a crucial role in the process of memory consolidation. Generation of SWR activity requires an intricate interaction between pyramidal cells and specific classes of GABAergic interneurons. Though(More)
BACKGROUND Many sedative agents, including anesthetics, produce explicit memory impairment by largely unknown mechanisms. Sharp-wave ripple (SPW-R) complexes are network activity thought to represent the neuronal substrate for information transfer from the hippocampal to neocortical circuits, contributing to the explicit memory consolidation. In this study(More)