Activation of ERK and JNK MAP kinases in optic nerves of rats exposed to global cerebral ischemia.
OBJECTIVE
To determine the influence of global cerebral ischemia on the activation of extracellular-regulated kinases (ERK) and c-Jun N-terminal kinases (JNK) in optic nerves of rats exposed to different reperfusion periods.


METHODS
Transient global cerebral ischemia (20-min duration) was induced by the four-vessel occlusion method. After different reperfusion periods (5 and 10 min; 1; 6 and 12 h after ischemia), optic nerves were extracted and ERK and JNK activation signals were determined by Western immunoblot analyses.


RESULTS
The activation signals of ERK and JNK were detected within first 10 min of reperfusion, but striking activation for both enzymes was found 1 h after ischemia. After a transient decrease, the activation of ERK returned to peak level after 12 h of reperfusion in the second wave of kinase activation. In that period, a slight increase of JNK activation was registered.


CONCLUSIONS
Our results demonstrated for the first time that ERK and JNK were activated in rat optic nerves during early and later periods of reperfusion, suggesting their potential active role in the response of cerebral white matter tissue to ischemic injury.
Mrsić-Pelcić
Jasenka
J
Department of Pharmacology, School of Medicine, University of Rijeka, Croatia. Jasenka.Mrsic@medri.hr
Pelcić
Goran
G
Vitezić
Dinko
D
Ljubicić
Dulijano
D
Zupan
Gordana
G
Simonić
Ante
A
D000818:Animals; D015153:Blotting, Western; D001921:Brain / Q000473:pathology; D002545:Brain Ischemia / Q000235:genetics* / Q000473:pathology; D004789:Enzyme Activation / Q000235:genetics; D048049:Extracellular Signal-Regulated MAP Kinases / Q000235:genetics*; D007124:Immunoenzyme Techniques; D048031:JNK Mitogen-Activated Protein Kinases / Q000235:genetics*; D009900:Optic Nerve / Q000098:blood supply* / Q000473:pathology; D051381:Rats; D017208:Rats, Wistar / Q000235:genetics; D015427:Reperfusion Injury / Q000235:genetics* / Q000473:pathology; D014715:Vertebrobasilar Insufficiency / Q000235:genetics / Q000473:pathology
D048049:Extracellular Signal-Regulated MAP Kinases; D048031:JNK Mitogen-Activated Protein Kinases