Alexander A. Velumian

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AMPA receptors (AMPARs) are not thought to be involved in the induction of long-term potentiation (LTP), but may be involved in its expression via second messenger pathways. However, one subunit of the AMPARs, GluR2, is also known to control Ca2+ influx. To test whether GluR2 plays any role in the induction of LTP, we generated mice that lacked this(More)
Neuropathic pain is a common and often incapacitating clinical problem for which little useful therapy is presently available. Painful peripheral neuropathies can have many etiologies, among which are trauma, viral infections, exposure to radiation or chemotherapy, and metabolic or autoimmune diseases. Sufferers generally experience both pain at rest and(More)
Using the whole-cell recording technique, we have examined the slow Ca(2+)-activated afterhyperpolarization (AHP) and its underlying current (IAHP) in hippocampal CA1 neurones of brain slices obtained from mature rats. Specifically we have studied the effects of the anion component of various K+ salts commonly used to make the pipette filling solution that(More)
Previously, we reported that the spike frequency adaptation and slow afterhyperpolarizations (sAHP) in hippocampal pyramidal neurones are best preserved during whole-cell recording with a methylsulfate (MeSO4-)- based internal solution, but undergo a fast rundown when gluconate- (Gluc-)- based internal solution is used. Here we show, with internal perfusion(More)
Following an initial impact after spinal cord injury (SCI), there is a cascade of downstream events termed 'secondary injury', which culminate in progressive degenerative events in the spinal cord. These secondary injury mechanisms include, but are not limited to, ischemia, inflammation, free radical-induced cell death, glutamate excitotoxicity,(More)
1. In hippocampal CA1 neurons of rat brain slices, a Ca(2+)-dependent slow afterhyperpolarization (sAHP) and underlying K+ current (IsAHP) are activated by Ca2+ influx and presumably reflect the time course of the intracellular Ca2+ signal produced by neuronal stimulation. We tested the hypothesis that when exogenous Ca2+ chelators become the predominant(More)
Gap junctions are cytoplasmic channels connecting adjacent cells and mediating their electrical and metabolic coupling. Different cell types in the CNS express various gap junction forming proteins, the connexins, in a cell-specific manner. Using the general gap junctional blocker, carbenoxolone, and two synthetic connexin mimetic peptides, corresponding to(More)
Astrocyte and neuronal development was investigated in organotypic brain slice cultures from mouse fetuses with a null mutation in the connexin43 gene. Astrocyte morphology and electrical properties were indistinguishable in null mutant slices and control slices but at 18 days in vitro astrocyte density in the central regions of the null mutant slices was(More)
We developed a technique of whole cell patch-clamp recordings from white matter oligodendrocytes and astrocytes in 200-250 microm-thick horizontal slices of adult (>2 months, 240-260 g) rat thoracic spinal cord. The viability of the white matter, sectioned in Na(+)-free, low Ca(2+) media, and the function of axons were preserved for >8 h, as demonstrated by(More)
PURPOSE In this study, we assessed the effects of topiramate (TPM) on high-voltage-activated calcium channel (HVACC) currents in vitro. METHODS HVACC currents were recorded from rat dentate gyrus granule cells by using whole-cell patch-clamp techniques. The biophysical properties of HVACCs were used to separate voltage-activated Ca2+ currents into(More)