title: Glutamate carboxypeptidase II (NAALADase) inhibition as a novel therapeutic strategy.
abstract: GCP II inhibition decreases extracellular excitotoxic glutamate and increases extracellular NAAG, both of which provide neuroprotection. We have demonstrated with our potent and selective GCP II inhibitors efficacy in models of stroke, ALS and neuropathic pain. GCP II inhibition may have significant potential benefits over existing glutamate-based neuroprotection strategies. The upstream mechanism seems selective for excitotoxic induced glutamate release, as GCP II inhibitors in normal animals induced no change in basal glutamate. This suggestion has recently been corroborated by Lieberman and coworkers24 who found that both NAAG release and increase in GCP II activity appear to be induced by electrical stimulation in crayfish nerve fibers and that subsequent NAAG hydrolysis to glutamate contributes, at least in part, to subsequent NMDA receptor activation. Interestingly, even at relatively high doses of compounds, GCP II inhibition did not appear to be associated with learning/memory deficits in animals. Additionally, quantitative neurophysiological testing data and visual analog scales for 'psychedelic effects' in Phase I single dose and repeat dose studies showed GCP II inhibition to be safe and well tolerated by both healthy volunteers and diabetic patients. GCP II inhibition may represent a novel glutamate regulating strategy devoid of the side effects that have hampered the development of postsynaptic glutamate receptor antagonists.
authors.affiliation: Guilford Pharmaceuticals Inc., 6611 Tributary Street, Baltimore, Maryland 21224, USA.
authors.forename: Ajit G
authors.initials: AG
authors.lastname: Thomas
authors.forename: Krystyna M
authors.initials: KM
authors.lastname: Wozniak
authors.forename: Takashi
authors.initials: T
authors.lastname: Tsukamoto
authors.forename: David
authors.initials: D
authors.lastname: Calvin
authors.forename: Ying
authors.initials: Y
authors.lastname: Wu
authors.forename: Camilo
authors.initials: C
authors.lastname: Rojas
authors.forename: James
authors.initials: J
authors.lastname: Vornov
authors.forename: Barbara S
authors.initials: BS
authors.lastname: Slusher
mesh_terms: D000700:Analgesics / Q000737:chemistry / Q000378:metabolism; D000818:Animals; D001224:Aspartic Acid / Q000031:analogs & derivatives / Q000737:chemistry / Q000378:metabolism; D004151:Dipeptides / Q000737:chemistry / Q000378:metabolism; D043425:Glutamate Carboxypeptidase II / Q000037:antagonists & inhibitors* / Q000235:genetics / Q000378:metabolism*; D018698:Glutamic Acid / Q000737:chemistry / Q000378:metabolism; D006801:Humans; D015394:Molecular Structure; D009474:Neurons / Q000378:metabolism / Q000473:pathology; D018696:Neuroprotective Agents / Q000737:chemistry / Q000378:metabolism; D009943:Organophosphorus Compounds / Q000737:chemistry / Q000378:metabolism
chemical_list: C402107:2-(phosphonomethyl)pentanedioic acid; D000700:Analgesics; D004151:Dipeptides; D018696:Neuroprotective Agents; D009943:Organophosphorus Compounds; C027172:isospaglumic acid; D001224:Aspartic Acid; D018698:Glutamic Acid; C000179:N-acetylaspartate; D043425:Glutamate Carboxypeptidase II