levorphanol and Brain-Ischemia

The N-methyl-D-aspartate (NMDA) antagonists dextromethorphan (DM) and dextrorphan (DX) were found to reduce significantly neocortical severe ischemic neuronal damage (SIND) when administered in a delayed fashion after the ischemic insult. Rabbits underwent occlusion of the left internal carotid artery and anterior cerebral artery for 1 h, followed by 4 h of reperfusion. Immediately after the completion of the 1 h arterial occlusion, animals were blindly treated intravenously with 20 mg/kg loading dose followed by 10 mg/kg/h of DM, 15 mg/kg loading dose followed by 15 mg/kg/h of DX, or an equivalent volume of normal saline (NS) alone. The area of neocortical SIND was 3.7% in the DM group, 4.4% in the DX group, and 41.3% in the normal saline controls. These drugs may have considerable therapeutic potential in clinical stroke.

Topics: Animals; Aspartic Acid; Brain Ischemia; Dextromethorphan; Dextrorphan; Levorphanol; Male; Morphinans; N-Methylaspartate; Rabbits

We assessed the cerebral protective effects of the noncompetitive N-methyl-D-aspartate antagonist dextromethorphan (DM; 10-35 mg/kg i.p.) in 8-day-old rats that were subjected to brain hypoxia-ischemia by tying one carotid artery and placing them in 8% O2-92% N2 for 2 h. Light microscopic examination of brains perfused one week after the insult revealed that all control animals developed a frank infarction with cavitation and brain shrinkage in the middle cerebral artery territory. There was a highly significant decrease in the incidence of frank infarction in DM-pre-treated pups vs saline-treated littermates, although there was no clear relationship between drug dose and the degree of brain protection. DM and its active metabolite dextrorphan may prove to be clinically useful in protecting against hypoxia-ischemia.

Topics: Animals; Brain; Brain Ischemia; Cerebral Infarction; Dextromethorphan; Dose-Response Relationship, Drug; Female; Levorphanol; Male; Rats; Rats, Inbred Strains

We investigated dextromethorphan, both a dextrorotatory opioid derivative and a clinically tested N-methyl-D-aspartate (NMDA) receptor antagonist, in a rabbit model of transient focal cerebral ischemia. Fourteen rabbits were randomly assigned to treatment with a 20 mg/kg i.v. loading dose followed by a 10 mg/kg/hr infusion of 0.4% dextromethorphan in normal saline or with an equivalent volume of normal saline alone. One hour after treatment, the rabbits underwent a 1-hour occlusion of the left internal carotid and anterior cerebral arteries followed by 4 hours of reperfusion. The seven dextromethorphan-treated rabbits showed a significant decrease in the area of neocortical severe ischemic neuronal damage (10.5%) compared with the seven normal saline-treated controls (49.6%, p less than 0.001). The dextromethorphan-treated rabbits also demonstrated significantly smaller areas of cortical edema (10.2%) on magnetic resonance imaging than the controls (38.6%, p less than 0.01). Analysis of somatosensory evoked potentials revealed recovery of the ipsilateral amplitude to contralateral values within 5 minutes of reperfusion in the dextromethorphan-treated rabbits but not in the controls (p less than 0.01). In our rabbit model of transient focal cerebral ischemia, dextromethorphan appears to protect the brain against ischemic neuronal damage and edema, as well as to promote neurophysiologic recovery. This clinically available drug should be further investigated as having potential therapeutic value in the treatment of stroke.

Topics: Animals; Brain; Brain Ischemia; Dextromethorphan; Dextrorphan; Evoked Potentials, Somatosensory; Levorphanol; Magnetic Resonance Imaging; Male; Neurons; Rabbits; Reference Values

The dextrorotatory opioid derivatives, dextrorphan and dextromethorphan, can attenuate hypoxic injury in cortical cell cultures. This effect is concentration-dependent in the micromolar range, and not strongly stereospecific, as it can also be demonstrated with the levorotatory enantiomer of dextrorphan, levorphanol. The possibility that these clinically available compounds may have therapeutic utility in hypoxic or ischemic encephalopathy warrants further investigation.

Topics: Animals; Brain Ischemia; Cells, Cultured; Cerebral Cortex; Dextromethorphan; Dextrorphan; Hypoxia; Levorphanol; Mice; Morphinans; Neurons

Topics: Animals; Brain Ischemia; Cerebrovascular Disorders; Gerbillinae; Hemiplegia; Levorphanol; Male; Morphine; Naloxone; Receptors, Opioid