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Mouse Hippocampal Slices (mouse + hippocampal_slice)

Distribution by Scientific Domains

Medical Sciences	50%

Selected Abstracts

Cellular mechanisms of cobalt-induced hippocampal epileptiform discharges

EPILEPSIA, Issue 1 2009
Jiwei He
Summary Purpose:, To explore the cellular mechanisms of cobalt-induced epileptiform discharges in mouse hippocampal slices. Methods:, Hippocampal slices were prepared from adult mice and briefly exposed to a CoCl2 -containing external solution. Population and single cell activities were examined via extracellular and whole-cell patch recordings. Results:, Brief cobalt exposure induced spontaneous, ictal-like discharges originating from the CA3 area. These discharges were suppressed by anticonvulsants, gap junction blockers, or by raising extracellular Ca2+, but their generation was not associated with overall hyperexcitability or impairment in GABAergic inhibition in the CA3 circuit. Electroencephalographic ictal discharges of similar waveforms were observed in behaving rats following intrahippocampal cobalt infusion. Discussion:, Mechanisms involving activity-dependent facilitation of gap junctional communication may play a major role in cobalt-induced epileptiform discharges. [source]

CD4+CD25, effector T-cells inhibit hippocampal long-term potentiation in vitro

EUROPEAN JOURNAL OF NEUROSCIENCE, Issue 6 2007
Gil M. Lewitus
Abstract During neuroinflammation T-cells invade the CNS, and may lead to the development and progression of several pathologies, of which multiple sclerosis is the most common. In these pathologies neuroinflammation is often associated with cognitive dysfunction. Using mouse hippocampal slices, we show here that CD4+CD25, T-cells inhibit long-term potentiation (LTP) induced by high-frequency stimulation. The T-cell-mediated inhibition of LTP can be prevented by blockade of ,-aminobutyric acid (GABA)A receptors. These findings provide additional insight into the multiple functions of T-cells in CNS pathologies. [source]

Ionic currents underlying rhythmic bursting of ventral mossy cells in the developing mouse dentate gyrus

EUROPEAN JOURNAL OF NEUROSCIENCE, Issue 7 2003
Shozo Jinno
Abstract The electrophysiological properties of mossy cells were examined in developing mouse hippocampal slices using whole-cell patch-clamp techniques, with particular reference to the dorsoventral difference. Dorsal mossy cells exhibited a higher spontaneous excitatory postsynaptic potential (EPSP) frequency and larger maximal EPSP amplitude than ventral mossy cells. On the other hand, the blockade of synaptic inputs with glutamatergic and GABAergic antagonists disclosed a remarkable dorsoventral difference in the intrinsic activity: none (0/27) of the dorsal mossy cells showed intrinsic bursting, whereas the majority (35/47) of the ventral mossy cells exhibited intrinsic rhythmic bursting. To characterize the ionic currents underlying the rhythmic bursting of mossy cells, we used somatic voltage-clamp recordings in the subthreshold voltage range. Ventral bursting cells possessed both hyperpolarization-activated current (Ih) and persistent sodium current (INaP), whereas dorsal and ventral nonbursting cells possessed Ih but no INaP. Blockade of Ih with cesium did not affect the intrinsic bursting of ventral mossy cells. In contrast, the blockade of INaP with tetrodotoxin or phenytoin established a stable subthreshold membrane potential in ventral bursting cells. The current,voltage curve of ventral bursting cells showed a region of tetrodotoxin-sensitive negative slope conductance between ,55 mV and a spike threshold (, ,45 mV). On the other hand, no subthreshold calcium conductances played a significant role in the intrinsic bursting of ventral mossy cells. These observations demonstrate the heterogeneous electrophysiological properties of hilar mossy cells, and suggest that the subthreshold INaP plays a major role in the intrinsic rhythmic bursting of ventral mossy cells. [source]

Fast Effects of Glucocorticoids on Memory-Related Network Oscillations in the Mouse Hippocampus

JOURNAL OF NEUROENDOCRINOLOGY, Issue 5 2008
E. K. Weiss
Transient or lasting increases in glucocorticoids accompany deficits in hippocampus-dependent memory formation. Recent data indicate that the formation and consolidation of declarative and spatial memory are mechanistically related to different patterns of hippocampal network oscillations. These include gamma oscillations during memory acquisition and the faster ripple oscillations (approximately 200 Hz) during subsequent memory consolidation. We therefore analysed the effects of acutely applied glucocorticoids on network activity in mouse hippocampal slices. Evoked field population spikes and paired-pulse responses were largely unaltered by corticosterone or cortisol, respectively, despite a slight increase in maximal population spike amplitude by 10 ,m corticosterone. Several characteristics of sharp waves and superimposed ripple oscillations were affected by glucocorticoids, most prominently the frequency of spontaneously occurring sharp waves. At 0.1 ,m, corticosterone increased this frequency, whereas maximal (10 ,m) concentrations led to a reduction. In addition, gamma oscillations became slightly faster and less regular in the presence of high doses of corticosteroids. The present study describes acute effects of glucocorticoids on sharp wave-ripple complexes and gamma oscillations in mouse hippocampal slices, revealing a potential background for memory deficits in the presence of elevated levels of these hormones. [source]