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~ATE OF PROGRESSION OF AMYOTROPHIC LATERAL SCLEROSIS CORRELATES WITH SERUM LEVELS OF EXCITATORY AMINO ACIDS ~ERNARD M. PATTEN, M.D., F,A.C.P, ET AL. BAYLOR COLLEGE OF MEDICINE, HOUSTON WE STUDIED SERUM, CEREBROSPINAL FLUID, AND URINE AMINO ACID LEVELS IN 12 ALS PATIENTS AND 12 AGE AND SEX MATCHED NEUROLOGICALLY DISEASED CONTROLS. ALS PATIENTS HAD STATISTICALLY SIGNIFICANT ELEVATIONS IN SERUM LEVELS OF TYROSINE, TOTAL AROMATIC, AND TOTAL BASIC AMINO ACIDS. THE SEVERITY OF ALS CORRELATED INVERSELY WITH SPINAL FLUID GLUTAMATE AND ASPARTATE AND ACTIVITY OF ALS CORRELATED DIRECTLY WITH SERUM ASPARTATE AND GLUTAMATE (R=+0.808, P<0.0Ol). AVERAGE ASPARTATE LEVELS IN SPINAL FLUID IN ALS EXCEEDED ASPARTATE LEVELS IN CONTROLS BY 2.75, THE ONLY AMINO ACID TO DIFFER FROM CONTROLS BY MORE THAN TWO FOLD WITH TRYPTOPHAN THE NEXT HIGHEST WITH A RATIO OF 1.58. ONE COULD SPECULATE THAT THE FIBRILLATIONS, FASCICULATIONS, CRAMPS, HYPEREFLEXIA, CLONUS AND POSSIBLY EVEN THE PROGRESSIVE WEAKNESS IN ALS MIGHT RELATE TO EXCESSIVE EXCITATORY AMINO ACID ACTIVITY. ADMINISTRATION OF L-THREONINE (METABOLICALLY CONVERTED TO GLYCINE IN THE CENTRAL NERVOUS SYSTEM) AND DEXTROMETHORPHAN (BLOCKS THE ASPARTATE RECEPTOR) IMPROVED CLINICAL FUNCTIONING IN SOME ALS PATIENTS.

103 GLUTAMATE BINDING SITES IN THE SUBSTANTIA NIGRA OF PARKINSON'S DISEASE JB Penney, MC Difazio, AB Young, University of Michigan, Ann Arbor, M148104-1687 USA Excitotoxins acting via NMDA receptors have been suggested as a cause of the Guamanian ALS-Parkinson's-dementia complex. We measured glutamate binding sites in 20 micron frozen sections of substantia nigra from Parkinson's (PD) and control brains. NMDA binding sites (8 PD, 8 control) were measured with 30 min incubations in 200 nM [3H]glutamate in 50 mM Tris-acetate, pH 7.4 at 40(3 (non specific binding determined in lmM NMDA). Three other binding sites (10 PD, 12 control) were measured in 50 mM Tris-HC1 + 2.5 mM CaCI 2+ 100 mM KSCN, pH 7.2 at 40C for 45 min. Ionotropic quisqualate receptors were measured with 37 nM [3H] AMPA (nonspecific binding determined in 1 mM glutamate). Metabotropic quisqualate receptors were measured with 200 nWl [3H] glutamate in the presence of 100 uM NMDA + 10 uM AMPA (nonspecifie binding determined in 2.5 uM quisqualate). Non-NMDA-, non-quisqualate-, non-kainate-sensitive (NNKQ) 200nM [3HI glutamate binding in the presence of 1 mM NMDA, 2.5 uM quisqualate + 1 uM kainate that was displaceable by 1 mM glutamate was also measured. NMDA binding sites in control brains were very low and reduced from 20_+7(sem) to 2.6+1.1 fmol/mg protein in the PD nigras (p<.01). NNKQ binding sites were reduced from 85+9 to 50_+12 fmol/mg protein (p<.04) in PD nigra. The ionotropic and metabotropic quisqualate sites were unchanged. These findings suggest that NMDA and NNKQ binding sites are present on the human substantia nigra pars compacta neurons that degenerate in PD. The very low number of NMDA binding sites suggest that factors other than excitotoxicity mediated via NMDA receptors on nigral cell bodies play roles in PD. NNKQ glutamate binding sites appear to be located on neurons but their role in normal nervous system function and human disease remain to be explored. Supported by the Michigan Parkinson Foundation, the Kenneth E Campbell Foundation, the Markey Trust and USPHS grants NS15655 and AG06155.

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MASSIVE RISE IN NE LEVELS 1N RAT HIPPQ~AMPI,/$ DI, IRIN(~ TRANSIENT I$~HEMIA, MEASURED BY MICRODIALYSIS. Perego C., Gatti S.,Marconi M.,Vetrugno G.C. Marzatico F.*, Benzi G.*, Algeri S. 1st. Ric. Farmacol. "Mario Negri"Via Eritrea 62 20157 Milano. ITALIA. *F.S.M.F.N. Univesith di Pavia. Several authors propose that NE has a protective role against neuronal cell death in the hippocampus, while others suggest that NE may be responsible for injurious effects of cerebral ischemia.We employed microdialysis techique to study extracellular NE levels in the rat hippocampus before, during,and after 30 minutes of transient incomplete ischemia induced by occlusion of four vessels (Pulsinelli model). One day before the experiment the rats vertebral arteries were cauterized and a transversal microdialysis probe was stereotaxicalty placed in the dorsal hippocampus .The day of the experiment the animals were anesthetized with halothane and subsequently ventilaled by a rodent respirator with a mixture of 0.75% halothane,30% oxygen,70% N20.Samples were collected every 10 minutes and ischemia was induced after lh of constant baseline (0.047 + 0,001 pmoles/10 min.~. Exlracellular NE levels were trebled after 20 minutes of ischemia.The maximal increase (five times) was in the two samples obtained in the last 10 minutes of ischemia and the first 10 minutes of reflow. NE levcls had returned to the baseline 40 minutes after release of the carotid clamps and remained constant during the remaining 80 minutes of reflow.These data show that extracellular NE levels are elevated during iscbemic episodes and immediately after removal of the clamps, underlining the important role of NE in ischemia.