This review focuses on the in vitro and in vivo neuropharmacology of YM872, a potential neuroprotective agent currently undergoing clinical trials in the United States (trial name: AMPA Receptor Antagonist Treatment in Ischemic Stroke -ARTIST). Its neuroprotective properties in rats and cats with induced focal cerebral ischemia are described. YM872, [2,3-dioxo-7-(1H-imidazol-1-yl)-6-nitro-1,2,3,4-tetrahydroquinoxalin-1-yl]-acetic acid monohydrate, is a selective, potent and highly water-soluble competitive á-amino-3-hydroxy-5-methylisoxazole-4-propionic acid (AMPA) receptor antagonist. YM872 has a potent inhibitory effect on [ 3 H]AMPA binding with a K i value of 0.096 ìM. In contrast, YM872 has very low affinity for other ionotropic glutamate receptors. The solubility of YM872 is approximately 500 to 1000 times higher than that of the other competitive AMPA antagonists: YM90K, NBQX, or CNQX. The neuroprotective efficacy of YM872 was investigated in rats and cats subjected to permanent occlusion of the left middle cerebral artery. The animals were assessed either histologically or neurologically following ischemia. In rats with occluded middle cerebral artery (MCAO) YM872, by i.v. infusion, significantly reduced infarct volume measured at 24 h and 1 week after ischemia. Significant neuroprotection was maintained even when drug administration was delayed 337

A novel alpha-amino-3-hydroxy-5-methylisoxazole-4-propionic acid (AMPA) receptor antagonist, YM872, may have an analgesic effect on both acute and chronic pain when administered intrathecally.

Summary:We studied the effect of a novel a-amino-3-hydroxy-5-methylisoxazole-4-propionic acid (AMPA)I kainate antagonist, YM90K [6-(IH-imidazol-1-yl)-7-nitro-2, 3(1H, 4H)-quinoxalinedione monohydrochloride], in a focal cerebral ischemia model using anesthetized cats. Cats were subjected to permanent occlusion of the middle cerebral artery (MCA) for 6 h, then killed and examined histologically. The amount of ischemic damage was as sessed in 12 stereotaxic coronal sections. Treatment with YM90K (i. v. infusion of 0.5 mg/5 mllkg/h) starting JO min after MCA occlusion markedly reduced the volume of ischemic damage (from 2823 ± 164 mm' of the cerebral The excessive increase of glutamate in the syn aptic cleft following ischemic is considered to play a critical role in the development of neuronal damage.Evidence for this comes from the finding that ischemic cell damage in the hippocampus is pro tected by surgical transection of ipsilateral gluta matergic afferents to the hippocampus in global -----------------��-.-�

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A non-subjective automated method for measuring spontaneous pain behaviour in an animal model of neuropathic pain was established. It is expected that the current system will greatly enhance the analysis of spontaneous pain-related behaviour, which is a predominant symptom in patients with neuropathic pain. The current system may also be valuable in the screening of potential analgesic treatments.