title: NMDA receptor blockade and spinal cord ischemia due to aortic crossclamping in the rat model.
abstract: Recent brain research proposes that, during ischemia, synaptically released excitatory amino acid neurotransmitters accumulate at toxic concentrations with ensuing neuronal death. Their action is mediated by the receptor subtype N-methyl-D-aspartate (NMDA). The protective effect of NMDA receptor blockade with intrathecal MgSO4 and MK-801 was investigated during spinal cord ischemia induced by aortic occlusion of 12 minutes. Male Sprague-Dawley rats, 250-300g, underwent intrathecal administration of 20 microL of normal saline (SA n = 16), MgSO4 1M (MG n = 16), or MK-801, 25 mM solutions (MK n = 16) in a randomized order. After 2 hours, the animals underwent occlusion of the thoracic aorta and subclavian arteries for 12 min. An additional control group (CO n = 16) underwent occlusion for 12 minutes, without intrathecal injection. The animals were scored according to their functional performance (LS = lesion score) each day for four days by a blinded observer. Mean LS were calculated for each group at a given day. Treatment and control groups were not different at day 1 (P = 0.302). Group MG was improved from groups SA (P = < 0.0039) and CO (P = < 0.0048) at day 4. This study demonstrates that although intrathecal NMDA receptor blockade with MgSO4 or MK-801 does not prevent paraplegia due to spinal cord ischemia in the rat, it could however influence the rate of recovery after ischemic injury.
authors.affiliation: Department of Thoracic and Cardiothoracic Surgery, University of New Mexico, Albuquerque 87131.
authors.forename: F
authors.initials: F
authors.lastname: Follis
authors.forename: K
authors.initials: K
authors.lastname: Miller
authors.forename: O U
authors.initials: OU
authors.lastname: Scremin
authors.forename: S
authors.initials: S
authors.lastname: Pett
authors.forename: R
authors.initials: R
authors.lastname: Kessler
authors.forename: J
authors.initials: J
authors.lastname: Wernly
mesh_terms: D000818:Animals; D001013:Aorta, Thoracic; D003250:Constriction; D004195:Disease Models, Animal; D016291:Dizocilpine Maleate / Q000008:administration & dosage / Q000494:pharmacology; D007278:Injections, Spinal; D007511:Ischemia / Q000473:pathology*; D008278:Magnesium Sulfate / Q000008:administration & dosage / Q000494:pharmacology; D008297:Male; D009460:Neurologic Examination; D010865:Pilot Projects; D051381:Rats; D017207:Rats, Sprague-Dawley; D016194:Receptors, N-Methyl-D-Aspartate / Q000037:antagonists & inhibitors*; D012039:Regional Blood Flow; D013116:Spinal Cord / Q000098:blood supply* / Q000473:pathology
chemical_list: D016194:Receptors, N-Methyl-D-Aspartate; D016291:Dizocilpine Maleate; D008278:Magnesium Sulfate