Susan A Lyons

Wake Forest School of Medicine · Institute for Regenerative Medicine

COPI recruitment to membranes appears to be essential for the biogenesis of the Golgi and for secretory trafficking. Preventing COPI recruitment by expressing inactive forms of the ADP-ribosylation factor (ARF) or the ARF-activating guanine nucleotide exchange factor GBF1, or by treating cells with brefeldin A (BFA), causes the collapse of the Golg...

Malignant gliomas have been shown to release glutamate, which kills surrounding brain cells, creating room for tumor expansion. This glutamate release occurs primarily via system xC, a Na+-independent cystine-glutamate exchanger. We show here, in addition, that the released glutamate acts as an essential autocrine/paracrine signal that promotes cel...

Although it is presynaptic, short-term plasticity has been shown at some synapses to depend upon the postsynaptic cell type. Previous studies have reported conflicting results as to whether Schaffer collateral axons have target-cell specific short-term plasticity. Here we investigate in detail the short-term dynamics of Schaffer collateral excitato...

Glial cells play an important role in sequestering neuronally released glutamate via Na+-dependent transporters. Surprisingly, these transporters are not operational in glial-derived tumors (gliomas). Instead, gliomas release glutamate, causing excitotoxic death of neurons in the vicinity of the tumor. We now show that glutamate release from glioma...

Voltage-gated chloride channels have recently been implicated as being important for cell proliferation and invasive cell migration of primary brain tumors cells. In the present study we provide several lines of evidence that glioma Cl- currents are primarily mediated by ClC-2 and ClC-3, two genes that belong to the ClC superfamily. Transcripts for...

Highly migratory neuroectodermal cells share a common embryonic origin with cells of the central nervous system (CNS). They include enteric, parasympathetic, sympathoadrenal, and sensory neurons of the peripheral nervous system, Schwann cells, melanocytes, endocrine cells, and cells forming connective tissue of the face and neck. Because of their c...

Neocortical freeze lesions have been widely used to study neuronal mechanisms underlying hyperexcitability in dysplastic cortex. Comparatively little attention has been given to biophysical changes in the surrounding astrocytes that show profound morphological and biochemical alterations, often referred to as reactive gliosis. Astrocytes are though...

The authors investigated the time course of leukocyte infiltration compared with microglial activation in adult rat brain slices after permanent middle cerebral artery occlusion (MCAO). To distinguish peripheral leukocytes from microglia, the blood cells were prelabeled in vivo with Rhodamine 6G (Rhod6G) i.v. before induction of ischemia. At specif...

Microglial cells are thought to serve as sensors for pathologic events in the brain. In the present study we demonstrate that these cells respond with an increase in intracellular calcium concentration ([Ca2+]i) to intracellular alkaline shifts induced by either application of NH3/NH4+ or by an extracellular alkaline shift. The cytoplasmic pH (pHi)...

The major classes of glial cells, namely astrocytes, oligodendrocytes, and microglial cells were compared in parallel for their susceptibility to damage after combined hypoxia and hypoglycemia or hypoxia alone. The three glial cell types were isolated from neonatal rat brains, separated, and incubated in N2/CO2-gassed buffer-containing glucose or g...

The cytokine, interleukin (IL)-15, and the T cell growth factor, IL-2, exhibit a similar spectrum of immune effects and share the IL-2 receptor (IL-2R) subunits IL-2Rbeta and IL-2Rgamma for signaling in hematopoietic cells. Numerous neuroregulatory activities of IL-2 have been suggested, but its expression in the normal central nervous system (CNS)...

We addressed the question of whether glial cells in intact white matter tracts express neurotransmitter receptors and we used Ca+2 signalling as a probe to detect the receptor activation. Corpus callosum slices from postnatal mice were bulk-loaded with the Ca+2-sensitive fluorescent dye fluo-3, and confocal microscopy was used to measure Ca+2 trans...

Schwann cells freshly isolated from the sciatic nerves of neonatal rats respond to exogenously applied ATP with a rapid increase in cytosolic calcium. This increase in [Ca2+]i is mediated by a P2Y-purinergic pathway (Lyons et al.: J. Neurochem. 63:552-560, 1994) and was measured using the calcium indicator dye, fura-2/AM, and a video-enhanced calci...

Schwann cells establish close contact with axons during development, and this is maintained throughout life. Signaling by neurotransmitters may play an important role in Schwann cell-axon interaction. Schwann cells were examined for the presence of neuroligland receptors that are linked to increases in levels of cytoplasmic calcium. Schwann cell cu...

Fetal rat dorsal root ganglion neurons (7-8 days in culture) were labeled with [3H]arachidonic acid for 24 h. Stimulation with 10 microM bradykinin (BK) for 30 s resulted in nearly 2-fold increases in levels of radioactive diglyceride and arachidonic acid. A similar result was obtained in the absence of receptor stimulation using the Ca2+ channel a...

Thesis (Ph. D.)--University of North Carolina at Chapel Hill, 1994. " ... in partial fulfillment of the requirements for the degree of Doctorate of Philosophy in the Department of Biochemistry and Biophysics." Includes bibliographical references (leaves : 66-76). Microfiche. s