Nikola Popov

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The water-soluble (cytosolic) and Lubrol-soluble (membrane-bound) calmodulin contents were determined radioimmunologically in fractions of striatum, hippocampus and cerebellum of dopamine supersensitive rats. Development of supersensitivity was the sequel of 3-weeks treatment of the animals with 1 mg/kg haloperidol or 5 mg/kg amphetamine i.p. daily. In the(More)
Acute and chronic experiments were performed to study the effects of intraperitoneally administered dopamine receptor agonists and antagonists on the translocation of cytosolic and membrane-bound calmodulin in the striatum and hippocampus of the rat brain. Single doses of apomorphine and a low-dose amphetamine (1.25 mg/kg) resulted in a translocation of(More)
The intraperitoneal or intraventricular application of L-fucose (100 mg/kg or 75 microgram, respectively) prior to training in shuttle box avoidance as well as in shock-motivated brightness discrimination in rats significantly improved the retention of learned behavior 24 hr later. The application of D-fucose was without influence on retention. In naive(More)
Using a brigthness discrimination model in rats, the labeling of discrete hippocampus formation structures was studied after intraventricular application of [3H]-fucose. This substance was injected 5 min before training as well as 5 min, 3, 7 and 23 h after training, the pulse period lasting 120 min in all cases. A significantly training-related enhanced(More)
Calmodulin content and immunoreactivity in rat brain structures, believed to be essential site involved in plasticity events, were determined by using biochemical and immunohistochemical methods, respectively. The levels of cytosolic and membrane-bound calmodulin paralleled the overall distribution pattern of calmodulin immunoreactivity. Very intense(More)
The content of cytosolic and membrane-bound calmodulin was radioimmunologically determined in fractions of rat hippocampal slices 5 min to 7 hours after long-term potentiation (LTP) had been induced by tetanization or exposure of slices to 4 mM Ca++. In light of concepts presuming multistage dynamics in LTP development as reflecting different cellular(More)
The content of calmodulin and S-100 protein in fractions of rat hippocampal slices was assayed by solid phase radioimmunology and radial immunodiffusion, respectively. One hour after tetanization (electrical stimulation of area dentata granular cells and recording from CA3 pyramids) an inverse translocation of these Ca++-binding proteins was observed: an(More)
The incorporation of intraventricularly infected L-[1-3H]fucose into proteins of the hippocampus and visual cortex was studied during the acquisition of a shock-motivated brightness discrimination in rats. The labeling of Tris-soluble proteins from both regions was not significantly changed during learning, whereas solubilized insoluble proteins obtained(More)
In rat hippocampal slices incubated in the presence of dopamine, a relatively strong correlation was observed between changes in the incorporation of 3H-fucose into total proteins and the formation of GDP-3H-fucose. However, in hippocampal homogenate the incorporation of 14C-fucose from GDP-14C-fucose was not stimulated by dopamine. In contrast, the(More)