The Gq/phospholipase C-linked human P2Y2 receptor was tagged at its amino terminus with the hemagglutinin A (HA) epitope sequence (P2Y2-HA) and stably expressed in 1321N1 human astrocytoma cells. Neither the pharmacological selectivity nor the signaling properties of the receptor were altered by the presence of the epitope. An enzyme-linked immunosorbent assay was developed to quantify cell sur...

Extracellular ATP and other nucleotides function as autocrine and paracrine signaling factors in many tissues. Recent studies suggest that P2 nucleotide receptors and ecto-nucleotidases compete for a limited pool of endogenously released nucleotides within cell surface microenvironments that are functionally segregated from the bulk extracellular compartment. To test this hypothesis, we have us...

Increases in cytoplasmic [Ca2+] caused by receptor activation are thought to stimulate the redistribution of loosely associated protein kinase C (PKC) to a tightly membrane-bound form that is activated by diacylglycerol. The precise role of Ca2(+)-dependent redistribution of PKC in the activation of this enzyme has not been critically assessed. We examined the relationship between PKC redistrib...

Though little attention has been given to the possibility that glial cells may represent a target for the developmental neurotoxicity of organophosphorus (OP) insecticides, recent evidence, obtained in particular with chlorpyrifos (CP), suggests that developmental exposure to this compound may indeed target astrocytes. To substantiate and expand these observations, we carried out a series of in...

Objective(s): Valproic and arundic acids are astrocytes-modulating agents with potential effects in the treatment of Alzheimer’s disease (AD). S100B is an astrocytic cytokine with a possible role in the pathogenesis of AD. In this study, we aimed to assess the glioprotective effects of valproic and arundic acids against amyloid-β-peptide (Aβ)-induced glial death and co...

glioblastoma is the most common and the most lethal primary brain cancer. this malignancy is highly locally invasive, rarely metastatic and resistant to current therapies. little is known about the distinct molecular biology of glioblastoma multiforme (gbm) in terms of initiation and progression. so far, several molecular mechanisms have been suggested to implicate in gbm development. homeodoma...

It has become increasingly clear that agents classically thought to act as neurotransmitters can also alter gene expression. To understand the early events by which neurotransmitters could effect genetic responses, we have studied the induction of two immediate early genes, c-fos and c-jun. These genes encode proteins that form a dimeric complex (AP-1) active as a transcriptional factor. Using ...

Incubation of 1321N1 human astrocytoma cells with carbachol resulted in a rapid loss of binding of [3H]N-methylscopolamine ([3H]NMS) to muscarinic cholinergic receptors measured at 4 degrees C on intact cells; loss of muscarinic receptors in lysates from the same cells measured with [3H]quinuclidinyl benzilate [( 3H]QNB) at 37 degrees C occurred at a slower rate. Upon removal of agonist from th...