K Dekermendjian

Learn More
Primary cultures of cerebral cortical neurons and single-cell imaging of intracellular free Ca2+ concentration ([Ca2+]i) with the ratiometric dye fura-2 were used to assess excitatory amino acid (EAA)-induced neurotoxicity; the loss of neuronal function as defined by the ability of the cells to respond to K(+)-induced depolarization by a transient increase(More)
The affinities for the benzodiazepine binding site of the GABA(A) receptor of 21 flavonoids have been studied using [(3)H]flumazenil binding to rat cortical membranes in vitro. We show that flavonoids with high affinity for the benzodiazepine receptor in vitro spanning the whole efficacy range from agonists (1q) to inverse agonists (1l) can be synthesized.(More)
The isolation and purification of a dopamine receptor ligand, tetrahydrocolumbamine from Polygala tenuifolia Willd is described. Tetrahydrocolumbamine was shown to inhibit the binding of [3H]-SCH23390 and [3H]-spiroperidol to rat striatum membranes in vitro with IC50 values of 0.75 +/- 0.08 mumol.L-1 and 0.92 +/- 0.10 mumol.L-1, respectively. The compound(More)
Eight furanocoumarins were isolated from a methanol extract of dried roots of Angelica dahurica. One of these, phellopterin, strongly (IC50 = 0.36 microM) inhibits the binding of [3H]diazepam to central nervous system benzodiazepine receptors in vitro, while the others, despite their structural similarities with phellopterin, are considerably less active.
Amyotrophic lateral sclerosis (ALS) is a chronic neurodegenerative disorder of the motor system in the CNS characterized by motor neuron death in the spinal cord, brain stem and cortex. Readily available tissues such as fibroblasts from ALS patients can serve as simple model systems to study the molecular mechanisms leading to degenerative disorders. We(More)
Phellopterin, a naturally occurring furanocoumarin found in the roots of Angelica dahurica, inhibits [3H]diazepam and ethyl 8-fluoro-5,6-dihydro-5-methyl-6-oxo-4H-imidazo[1,5-a][1,4] benzodiazepine-3-carboxylate ([3H]Ro 15-1788) binding to the benzodiazepine site of the rat brain gamma-aminobutyric acidA (GABAA) receptor in vitro with IC50 values of 400 and(More)
The resolution of synthetic (+/-)-isovelleral (1), via chromatographic separation of the two diastereomers of the (-)-menthoxyacetic acid diester of the corresponding (+/-)-diol (3), yielded both enantiomers of the bioactive fungal metabolite (+)-isovelleral (1). While the antimicrobial and cytotoxic activities of the two enantiomers are comparable, natural(More)
The data from the literature regarding the presence of a neurotoxic factor in amyotrophic lateral sclerosis (ALS) plasma or cerebrospinal fluid (CSF) remain controversial. As a new approach to this question, we have studied the effect of CSF from ALS patients on the temporal dynamics of the intracellular free calcium concentration ([Ca2+]i) of murine(More)
The effect of mutating the conserved amino acid residue arginine 120 to lysine in the GABAA receptor alpha 1 subunit was studied. In electrophysiological experiments, the arginine 120 lysine (R120K) mutation in the alpha 1 subunit, when co-expressed with beta 2 and gamma 2 subunits in Sf-9 insect cells, induces a 180-fold rightward shift of the GABA(More)
The gamma-aminobutyric acid (GABA) binding pocket within the GABA(A) receptor complex has been suggested to contain arginine residues. The aim of this study was to test this hypothesis by mutating arginine residues potentially contributing to the formation of a GABA binding pocket. Thus, six arginines conserved in human GABA(A) receptor alpha subunits(More)