Minerva Contreras

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K-252a, a kinase inhibitor isolated from the culture broth of Nocardiopsis sp., selectively inhibits the actions of nerve growth factor (NGF) on PC 12 cells. At a concentration of 200 nM, K-252a prevents neurite generation initiated by NGF, but not neurite generation produced by fibroblast growth factor or outgrowth produced by dibutyryl cAMP. K-252a also(More)
The interaction of methylmercury (MeHg) with neuronal Ca2+ channels in rat forebrain synaptosomes and dihydropyridine (DHP)-sensitive Ca2+ channels in rat pheochromocytoma (PC12) cells was examined using radiotracer flux assays and radioligand binding analyses. In synaptosomes, the influx of 45Ca2+ was used to examine the voltage and state dependence of(More)
The effect of nerve growth factor (NGF) on the hydrolysis of phosphoinositides in PC12 cells was examined. Addition of NGF to PC12 cells prelabeled with [3H]-inositol resulted in an increase in the formation of labeled inositol trisphosphate ([3H]IP3), inositol bisphosphate ([3H]IP2), and inositol monophosphate ([3H]IP), an observation indicating that NGF(More)
NFATc-mediated gene expression constitutes a critical step during neuronal development and synaptic plasticity. Although considerable information is available regarding the activation and functionality of specific NFATc isoforms, in neurons little is known about how sensitive NFAT nuclear translocation is to specific patterns of electrical activity. Here we(More)
The zebra finch telencephalon exhibits rapid and substantial development in the first few weeks after hatching. In parallel, the rate of estradiol synthesis is very high in the zebra finch forebrain, and estradiol can have potent neurotrophic effects in specific telencephalic regions, including those that control the learning and production of song. In an(More)
Tetanus toxin, a potent neurotoxin which blocks neurotransmitter release in the CNS, also inhibits Ca2+-induced catecholamine release from digitonin-permeabilized, but not from intact bovine chromaffin cells. In searching for intracellular targets for the toxin we studied the binding of affinity-purified tetanus toxin to bovine adrenal chromaffin granules.(More)
The effects of Aroclor 1254, a mixture of polychlorinated biphenyls (PCBs), on nerve growth factor (NGF) receptors and neurite outgrowth in PC12 cells were examined. Aroclor 1254 enhanced the NGF-stimulated neurite elongation and decreased the Kd value for binding of 125I-labeled NGF to the high-affinity NGF receptors. The NGF dose-response curve for(More)
The purpose of this study was to examine the binding and behavioral effects mediated by PCP and sigma receptors in the rat. From the radioreceptor assays, it was possible to characterize two binding sites that interact with PCP and sigma ligands. The two sites, a PCP and sigma receptor, could be differentiated based on drug selectivity and potency. In the(More)
INTRODUCTION Mercury is a high-priority regulatory concern because of its persistence and bioaccumulation in the environment and evidence of its having serious adverse effects on the neurological development of children. DISCUSSION Mercury is released into the atmosphere from both natural and anthropogenic sources. Coal-fired utilities are considered to(More)
In PC12 cells, preincubated with [3H]inositol, nerve growth factor (NGF) stimulated an approximately 100% increase in the levels of [3H]inositol 1,3,4-trisphosphate ([3H]-Ins(1,3,4)P3], [3H]inositol 1,4,5-trisphosphate ([3H]Ins(1,4,5)P3], and [3H]inositol 1,3,4,5-tetrakisphosphate ([3H]Ins(1,3,4,5)P4] as early as 5-15 s after addition of NGF. This(More)