TY - JOUR
T1 - Competitive NMDA receptor antagonists and spinal-cord ischemia
AU - Follis, Fabrizio
AU - Blisard, Karen
AU - Varvitsiotis, Poseidon S.
AU - Pett, Stuart B.
AU - Temes, Tom
AU - Wernly, Jorge A.
PY - 2000/3
Y1 - 2000/3
N2 - Ischemic neuronal death is associated with excitatory amino acid (EAA) release. Their action is mediated by N-methyl-D-aspartate (NMDA) receptors. Blockade of the receptors before the ischemic insult can decrease neuronal damage. Accordingly, we investigated the protective effect during spinal cord ischemia of two competitive antagonists, 4-(3-phosphonopropyl)-2-piperazine-carboxylic acid (CPP) and cis-4-(phosphonomethyl)-2-piperidine-carboxylic acid (CGS). Male Sprague-Dawley rats underwent intrathecal administration of 10 μL saline, CGS, and CPP 10 mM solutions, in a randomized blinded fashion, and were subjected to balloon occlusion of the thoracic aorta. Proximal aortic pressure was lowered to a mean of 40 mmHg by partial exsanguination. In the acute protocol, 21 rats divided in 3 groups of 7 (saline, CPP, and CGS) were used to calculate the aortic occlusion time (AOT) resulting in paraplegia in 50% of animals (P50). In the chronic study, 24 rats divided in 4 groups of 6 (saline, CPP, CGS, sham) underwent 12-min occlusion. The chronic animals were scored daily for 28 days and submitted to histology of the cord. In the acute study, the P50 of CGS (10 min 48 s) and CPP (11 min 11 s) was longer than saline (10 min 27 s). In the chronic groups, analysis of variance of neurologic (p = .66) and histologic (p = .66) scores did not disclose differences between CGS, CPP, and saline. In conclusion, blockade of NMDA receptors with CPP or CGS may afford some protection for durations of occlusion around the P50, but it is not beneficial when ischemic injury is more protracted.
AB - Ischemic neuronal death is associated with excitatory amino acid (EAA) release. Their action is mediated by N-methyl-D-aspartate (NMDA) receptors. Blockade of the receptors before the ischemic insult can decrease neuronal damage. Accordingly, we investigated the protective effect during spinal cord ischemia of two competitive antagonists, 4-(3-phosphonopropyl)-2-piperazine-carboxylic acid (CPP) and cis-4-(phosphonomethyl)-2-piperidine-carboxylic acid (CGS). Male Sprague-Dawley rats underwent intrathecal administration of 10 μL saline, CGS, and CPP 10 mM solutions, in a randomized blinded fashion, and were subjected to balloon occlusion of the thoracic aorta. Proximal aortic pressure was lowered to a mean of 40 mmHg by partial exsanguination. In the acute protocol, 21 rats divided in 3 groups of 7 (saline, CPP, and CGS) were used to calculate the aortic occlusion time (AOT) resulting in paraplegia in 50% of animals (P50). In the chronic study, 24 rats divided in 4 groups of 6 (saline, CPP, CGS, sham) underwent 12-min occlusion. The chronic animals were scored daily for 28 days and submitted to histology of the cord. In the acute study, the P50 of CGS (10 min 48 s) and CPP (11 min 11 s) was longer than saline (10 min 27 s). In the chronic groups, analysis of variance of neurologic (p = .66) and histologic (p = .66) scores did not disclose differences between CGS, CPP, and saline. In conclusion, blockade of NMDA receptors with CPP or CGS may afford some protection for durations of occlusion around the P50, but it is not beneficial when ischemic injury is more protracted.
KW - Ischemia
KW - N-methylaspartate
KW - Paraplegia
KW - Spinal cord
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M3 - Article
C2 - 10801049
AN - SCOPUS:0034054131
VL - 13
SP - 117
EP - 121
JO - Journal of Investigative Surgery
JF - Journal of Investigative Surgery
SN - 0894-1939
IS - 2
ER -