Effects of ifenprodil, a polyamine site NMDA receptor antagonist, on reperfusion injury after transient focal cerebral ischemia.
Polyamines and N-methyl-D-aspartate (NMDA) receptors are both thought to play an important role in secondary neuronal injury after cerebral ischemia. Ifenprodil, known as a noncompetitive inhibitor of polyamine sites at the NMDA receptor, was studied after transient focal cerebral ischemia occurred. Spontaneously hypertensive male rats, each weighing between 250 and 350 g, underwent 3 hours of tandem middle cerebral artery (MCA) and common carotid artery occlusion followed by reperfusion for a period of 3 hours or 21 hours. Intravenous ifenprodil (10 microg/kg/minute) or saline infusion was started immediately after the onset of MCA occlusion and continued throughout the ischemic period. Physiological parameters including blood pressure, blood gas levels, blood glucose, hemoglobin, and rectal and temporal muscle temperatures were monitored. Six rats from each group were evaluated at 6 hours postocclusion for brain water content, an indicator of brain edema, and Evans blue dye extravasation for blood-brain barrier breakdown. Infarct volume was also measured in six rats from each group at 6 and 24 hours postocclusion. Ifenprodil treatment significantly reduced brain edema (82.5 +/- 0.4% vs. 83.5 +/- 0.4%, p < 0.05) and infarct volume (132 +/- 14 mm3 vs. 168 +/- 25 mm3, p < 0.05) compared with saline treatment, with no alterations in temporal muscle (brain) or rectal (body) temperature (35.9 +/- 0.4 degrees C vs. 36.2 +/- 0.2 degrees C; 37.7 +/- 0.4 degrees C vs. 37.6 +/- 0.6 degrees C; not significant). These results demonstrate that ifenprodil has neuroprotective properties after ischemia/reperfusion injury in the absence of hypothermia. This indicates that antagonists selective for the polyamine site of the NMDA receptors may be a viable treatment option and helps to explain some of the pathophysiological mechanisms involved in secondary injury after transient focal cerebral ischemia has occurred.
Doğan
A
A
Department of Neurological Surgery, University of Wisconsin, and Veterans Administration Hospital, Madison 53792, USA.
Rao
A M
AM
Başkaya
M K
MK
Rao
V L
VL
Rastl
J
J
Donaldson
D
D
Dempsey
R J
RJ
D000317:Adrenergic alpha-Antagonists / Q000008:administration & dosage / Q000627:therapeutic use*; D000818:Animals; D001794:Blood Pressure / Q000187:drug effects; D001812:Blood-Brain Barrier / Q000187:drug effects; D001831:Body Temperature / Q000187:drug effects; D001834:Body Water / Q000737:chemistry / Q000187:drug effects; D001921:Brain / Q000187:drug effects / Q000378:metabolism; D001929:Brain Edema / Q000378:metabolism / Q000517:prevention & control; D002544:Cerebral Infarction / Q000473:pathology / Q000517:prevention & control; D004396:Coloring Agents; D005070:Evans Blue; D018691:Excitatory Amino Acid Antagonists / Q000008:administration & dosage / Q000627:therapeutic use*; D006454:Hemoglobins / Q000032:analysis; D007262:Infusions, Intravenous; D002546:Ischemic Attack, Transient / Q000188:drug therapy*; D008297:Male; D018696:Neuroprotective Agents / Q000008:administration & dosage / Q000627:therapeutic use*; D010100:Oxygen / Q000097:blood; D010880:Piperidines / Q000008:administration & dosage / Q000627:therapeutic use*; D051381:Rats; D011918:Rats, Inbred SHR; D016194:Receptors, N-Methyl-D-Aspartate / Q000037:antagonists & inhibitors*; D015427:Reperfusion Injury / Q000188:drug therapy*; D012965:Sodium Chloride; D013703:Temporal Muscle / Q000187:drug effects; D014665:Vasodilator Agents / Q000008:administration & dosage / Q000627:therapeutic use*
D000317:Adrenergic alpha-Antagonists; D004396:Coloring Agents; D018691:Excitatory Amino Acid Antagonists; D006454:Hemoglobins; D018696:Neuroprotective Agents; D010880:Piperidines; D016194:Receptors, N-Methyl-D-Aspartate; D014665:Vasodilator Agents; D012965:Sodium Chloride; D005070:Evans Blue; C010739:ifenprodil; D010100:Oxygen