cgp-37849 and Brain-Ischemia

The effect of the new competitive N-methyl-D-aspartate (NMDA) antagonist D-(E)-2-amino-4-methyl-5-phosphono-3-pentenoic acid (CAS 137424-81-8, CGP 40116) was evaluated in a rat four-vessel occlusion model and compared to the effect of another NMDA antagonist (+/-)-cis-4-phosphonomethyl-piperadine-2-carboxylic acid (CAS 110347-85-8, CGS 19755) under the same conditions. Drugs were administered intravenously immediately following occlusion. At 72 h after the ischemia, latency in the passive avoidance test was significantly shorter in ischemic control rats in comparison with sham-operated rats. CGP 40116 at the dose of 10 mg/kg and CGS 19755 at the doses of 10 and 30 mg/kg significantly lengthened the latency. At 2 weeks after ischemia, ischemic control rats showed no differences in latency compared to sham-operated rats. The number of survived neurons of control rats was significantly less than that of sham-operated rats at 72 h and 2 weeks after ischemia. CGP 40116 at the doses of 3 and 10 mg/kg and CGS 19755 at the doses of 10 and 30 mg/kg significantly increased the number of survived neurons. Adenosine triphosphate (ATP) level in striatum of control rats was significantly lower than that of sham-operated rats at 24 h after ischemia when an acquisition trial was performed in the passive avoidance test. CGP 40116 at the dose of 10 mg/kg and CGS 19755 at the dose of 30 mg/kg ameliorated the decrease. These results suggest that CGP 40116 might have an ameliorative effect on the memory deficits in the passive avoidance test after ischemic injuries through the suppression of changes in brain energy metabolism.

Topics: 2-Amino-5-phosphonovalerate; Adenosine Triphosphate; Animals; Avoidance Learning; Brain Chemistry; Brain Ischemia; Cerebrovascular Circulation; Energy Metabolism; Excitatory Amino Acid Antagonists; Male; Motor Activity; N-Methylaspartate; Rats; Rats, Inbred F344

The effect of the new competitive N-methyl-D-aspartate (NMDA) antagonist D-(E)-2-amino-4-methyl-5-phosphono-3-pentenoic acid (CAS 137424-81-8, CGP 40116) was examined in a cat model of focal cerebral ischemia. Effect of CGP 40116 was compared to that of another competitive NMDA antagonist, (+/-)-cis-4-phosphonomethyl-piperadine-2-carboxylic acid (CAS 110347-85-8, CGS 19755) under the same conditions. Drugs were administered intravenously 30 min before left middle cerebral artery (MCA) occlusion. After MCA occlusion for 8 h, infarction spreaded widely among caudate nucleus prepyriform cortex, amygdala and temporal lobe cortex in the ischemic hemisphere. CGP 40116 at the dose of 10 mg/kg and CGS 19755 at the dose of 30 mg/kg significantly decreased the infarcted area. CGP 40116 was effective in the frontal and central brain, although CGS 19755 showed neuroprotective effect in almost all sites. Thus, the compounds are potent neuroprotectants in focal ischemia.

Topics: 2-Amino-5-phosphonovalerate; Animals; Brain; Brain Ischemia; Cats; Cerebral Infarction; Excitatory Amino Acid Antagonists; Image Processing, Computer-Assisted; Male; Neuroprotective Agents; Pipecolic Acids; Receptors, N-Methyl-D-Aspartate

Focal cerebral ischemia was induced in rats by permanent occlusion of the left middle cerebral artery (MCA). The cerebroprotective properties of the competitive NMDA antagonist CGP 40116 were evaluated in that model and compared to the neuroprotective effects of MK 801, D-CPPene and CGS 19755 under the same experimental conditions. Infarct volume was assessed using in vivo magnetic resonance imaging. The rank order of potency for the NMDA antagonists tested was MK 801 > CGP 40116 approximately D-CPPene > CGS 19755. CGP 40116 dose-dependently reduced the volume of cortical infarction, with an ED50 of 11 mg/kg i.v., and its cerebroprotective efficacy was comparable to that of MK 801. Neuroprotection by CGP 40116 was still apparent when treatment was started 30 minutes after MCA occlusion. It is concluded that CGP 40116 is an effective cerebroprotectant with potential clinical utility for amelioration of focal cerebral ischemic damage.

Topics: 2-Amino-5-phosphonovalerate; Animals; Blood Pressure; Brain Ischemia; Dizocilpine Maleate; Dose-Response Relationship, Drug; Magnetic Resonance Imaging; Male; Neuroprotective Agents; Pipecolic Acids; Piperazines; Rats; Rats, Inbred F344; Receptors, N-Methyl-D-Aspartate

In the present study the in vitro and ex vivo distributions of [3H]dizocilpine binding sites in mouse brain after middle cerebral artery occlusion (MCA-O) were compared using receptor autoradiography. The distribution patterns of [3H]dizocilpine binding sites obtained in vitro and ex vivo in normal mouse brain were the same with the highest densities occurring in the hippocampus and cerebral cortex. MCA-O had little or no effect on the in vitro binding density for at least 24 hr post-ischaemia. However after 2-3 days binding densities in the region of infarct were significantly reduced compared to the contralateral cerebral cortex. Further reductions occurred after 5-7 days. By contrast ex vivo [3H]dizocilpine binding was reduced in the infarcted area by 78.7 +/- 4% within 2 hr of the ischaemic insult and at all subsequent times binding was reduced by more than 75%. Ex vivo binding after ischaemia was always less than 30% of in vitro binding and this decrease was apparent within 2 hr of the ischaemic insult whereas in vitro binding was maintained at control levels for at least 24 hr. The neuroprotective activity of the NMDA antagonists dizocilpine and CGP 37849 in this model at different times after MCA-O was assessed. The time scale for receptor access following MCA-O is discussed and it is suggested that although the population of NMDA receptors is maintained in the infarct region for some days access to them in vivo may be sufficiently impaired within 2 or 4 hr of ischaemic insult to reduce the neuroprotective activity of NMDA antagonists after this time.

Topics: 2-Amino-5-phosphonovalerate; Animals; Autoradiography; Binding Sites; Brain; Brain Ischemia; Cerebral Arteries; Cerebral Infarction; Dizocilpine Maleate; In Vitro Techniques; Male; Mice; Receptors, N-Methyl-D-Aspartate

The cerebroprotective properties of the competitive NMDA antagonist D-(E)-2-amino-4-methyl-5-phosphono-3-pentenoic acid (CGP 40116) were evaluated in a rat model of focal cerebral ischemia. CGP 40116 (5-40 mg/kg i.v.) was injected immediately following permanent occlusion of the left middle cerebral artery (MCA). MK 801 (1 or 3 mg/kg i.v.), D-CPPene (20 mg/kg i.v.), and CGS 19755 (40 mg/kg i.v.) were used for comparison. Lesion volume was assessed using in vivo magnetic resonance imaging, which in initial experiments with parallel histological determinations proved to be an accurate method for the measurement of brain infarction and the determination of a cerebroprotective drug effect. CGP 40116 dose-dependently reduced the volume of cortical infarction, with an ED50 of 11 mg/kg i.v. and a maximal effect equivalent to a 62% reduction in cortical edema volume. Its cerebroprotective efficacy was thus comparable to that of MK 801. The rank order of potency for the NMDA antagonists was MK 801 > CGP 40116 approximately D-CPPene > CGS 19755. Neuroprotection by CGP 40116 was still apparent when treatment was started 30 min after MCA occlusion. It is concluded that CGP 40116 is an effective cerebroprotectant with potential clinical utility for amelioration of focal cerebral ischemic damage.

Topics: 2-Amino-5-phosphonovalerate; Animals; Binding, Competitive; Brain; Brain Edema; Brain Ischemia; Cats; Magnetic Resonance Imaging; Rats; Receptors, N-Methyl-D-Aspartate; Time Factors

Focal cerebral ischaemia was induced in rats by occlusion of the left middle cerebral artery. Two days later, infarct volume was determined by magnetic resonance imaging and the concentrations of the polyamines putrescine (PU), spermine and spermidine by HPLC. In control (occluded) animals, PU levels were elevated in infarcted and non-infarcted areas of the left hemisphere. Treatment with the ornithine decarboxylase (ODC) inhibitor alpha-difluoromethylornithine, prevented the ischaemia-induced increase in tissue PU without affecting infarct volume. Conversely, administration of the N-methyl-D-aspartate (NMDA) receptor antagonist CGP 40116 decreased cortical infarction without changing the tissue content of PU. We conclude that there is no direct link between NMDA receptor activation and brain PU, or PU and post-ischaemic tissue damage, and that inhibitors of ODC are not cerebroprotective in this animal model of stroke.

Topics: 2-Amino-5-phosphonovalerate; Animals; Brain; Brain Ischemia; Cerebral Infarction; Eflornithine; Magnetic Resonance Imaging; Male; Ornithine Decarboxylase Inhibitors; Polyamines; Putrescine; Rats; Rats, Inbred F344; Spermidine; Spermine

Excitatory amino acids are implicated in the development of neuronal cell damage following periods of reversible cerebral ischemia or insulin-induced hypoglycemic coma. To explore the importance of glutamate receptor activation in the posthypoglycemic phase, we exposed rats to 20 min of insulin-induced severe hypoglycemia. The rats were treated immediately after the hypoglycemic insult with four regimes of glutamate receptor antagonists: (1) the AMPA (alpha-amino-3-hydroxy-5-methyl-4-isoxazole propriate)-receptor antagonist NBQX [2.3-dihydroxy-6-nitro-7-sulfamoyl-benzo (F) quinoxaline] given as a bolus dose of 30 mg.kg-1 i.p., followed by an i.v. infusion of 225 micrograms.kg-1.min-1 for 6 h; (2) the non-competitive NMDA-receptor antagonist, dizocilpine (MK-801) 1 mg.kg-1 given i.v.; (3) a combined NBQX treatment, (a bolus dose of 10 mg.kg-1 i.p., followed by an i.v. infusion of 225 micrograms.kg-1.min-1 for 6 h), with dizocilpine 0.33 mg.kg-1 given twice i.p. at 0 and 15 min after recovery and (4) the competitive NMDA-receptor blocker CGP 40,116 [D-(E)-2-amino-4-methyl-5-phosphono-3- pentenoic acid] 10 mg.kg-1 given i.p. In the striatum, all glutamate receptor blockers significantly decreased neuronal damage by approximately 30%. An approximately 50% decrease in neuronal damage was demonstrated in neocortex and hippocampus following the combined treatment with NBQX and dizocilpine, while protection was variable following the treatment with a single glutamate-receptor antagonist.(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: 2-Amino-5-phosphonovalerate; Animals; Blood Pressure; Brain Ischemia; Cell Death; Dizocilpine Maleate; Electroencephalography; Excitatory Amino Acid Antagonists; Insulin Coma; Male; Necrosis; Neurons; Quinoxalines; Rats; Rats, Wistar; Receptors, AMPA; Receptors, N-Methyl-D-Aspartate