fm1-43 and Brain-Ischemia

There is a major unmet need for development of innovative strategies for neuroprotection against ischemic brain injury. Here we show that FGL, a neural cell adhesion molecule (NCAM)-derived peptide binding to and inducing phosphorylation of the fibroblast growth factor receptor (FGFR), acts neuroprotectively after an ischemic insult both in vitro and in vivo. The neuroprotective activity of FGL was tested in vitro on dissociated rat hippocampal neurons and hippocampal slice cultures, using a protocol of oxygen-glucose deprivation (OGD). FGL protected hippocampal neurons from damage and maintained or restored their metabolic and presynaptic activity, both if employed as a pretreatment alone to OGD, and if only applied after the insult. In vivo 24 h pretreatment with a single suboccipital injection of FGL significantly protected hippocampal CA1 neurons from death in a transient global ischemia model in the gerbil. We conclude that FGL promotes neuronal survival after ischemic brain injury.

Topics: Animals; Animals, Newborn; Brain Ischemia; Cell Count; Cells, Cultured; Drug Interactions; Glucose; Hippocampus; Hypoxia; Neural Cell Adhesion Molecules; Neurons; Neuroprotective Agents; Organ Culture Techniques; Phosphorylation; Propidium; Pyridinium Compounds; Pyrroles; Quaternary Ammonium Compounds; Rats; Rats, Wistar; Receptors, Fibroblast Growth Factor; Synapses; Tetrazolium Salts; Thiazoles; Time Factors

The mechanism of glutamate release from cultured cerebellar granule neurones in response to a chemical model of ischaemia (10 mM 2-deoxyglucose plus 1 mM sodium cyanide) was investigated. In the first 2 min of ischaemia, release of preloaded D-[3H]aspartate could be extensively attenuated by tetanus toxin and bafilomycin A1 and was dependent on the activation of Ca2+ channels sensitive to the "Q" type Ca2+ channel antagonist, omega-conotoxin-MVIIC. During this period, ATP/ADP ratios fell rapidly. The extent of release in the first 2 min was comparable to that evoked by 2-min depolarization by 50 mM KCl. Free Ca2+ concentrations, determined in neurites and somata, did not increase until after 2 min. The neurite increase in cellular Ca2+ precedes that of the cell somata. Release of D-[3H]aspartate was partially inhibited by the NMDA receptor antagonist MK-801, which also delayed the increase in free Ca2+ concentration. Prolonging the period of ischaemia to 6 and 10 min produced no further increase in the apparently exocytotic component of release, but initiated an extensive nonexocytotic release of the amino acid. Studies with the synaptic vesicle membrane probe FM1-43 in which released amino acid was removed by superfusion indicated that Ca2+-dependent exocytosis was delayed in this system. It is concluded that chemical ischaemia initiates an initial exocytotic followed by nonexocytotic release and that the former is facilitated by NMDA receptor activation. These events occur in cells that are still able to exclude propidium iodide, indicating that cell death has not yet occurred.

Topics: Adenosine Diphosphate; Adenosine Triphosphate; Animals; Anti-Bacterial Agents; Aspartic Acid; Brain Ischemia; Calcium; Calcium Channel Blockers; Calcium Channels; Cells, Cultured; Cerebellum; Cytoplasm; Deoxyglucose; Dizocilpine Maleate; Exocytosis; Fluorescent Dyes; Glutamic Acid; Macrolides; Neurons; omega-Conotoxins; Peptides; Pyridinium Compounds; Quaternary Ammonium Compounds; Rats; Receptors, N-Methyl-D-Aspartate; Sodium Cyanide; Tetanus Toxin; Time Factors