The effect of global ischemia and recirculation of rat brain on protein synthesisin vitro

Abstract

Transient cerebral ischemia causes long-lasting inhibition of protein synthesis despite recovery of energy metabolism. We investigated the question if this inhibition is due to the formation of a suppression factor which interferes with the function of the protein synthesizing machinery. For this purpose rats were submitted to 20 minutes four vessel-occlusion followed by recirculation times from 30 minutes to 7 days. Post-mitochondrial supernatant (PMS) from various brain regions was added to a self-contained, cell-free rabbit reticulocyte translational system, and the effect on in vitro protein synthesis was assessed by measuring 14C-leucine incorporation over a duration of 45 minutes. PMS prepared at the end of ischemia from hippocampus, striatum and cerebellum inhibited in vitro protein synthesis by 40%-60% but there was only a minor inhibition by PMS from cerebral cortex. During post-ischemic recirculation cortical PMS transiently induced inhibition of in vitro protein synthesis by 30% but this effect gradually disappeared within one week. The inhibition caused by PMS from hippocampus, striatum and cerebellum was not reversed during recirculation and still amounted to about 40% after 7 days. Inhibition of in vitro protein synthesis could be blocked by heating PMS to 100 degrees C, indicating that the suppressor factor is a protein. The comparison of the in vitro effect of postischemic PMS with previously described in vivo inhibition of protein synthesis demonstrates that the here observed suppressor factor is not able to explain the overall disturbance of protein synthesis in vivo.(ABSTRACT TRUNCATED AT 250 WORDS)

Rapid Loss of Microvascular Integrin Expression during Focal Brain Ischemia Reflects Neuron Injury

“…Hossmann et al and others have suggested that a general regional shutdown in protein synthesis occurs during focal cerebral ischemia (Bodsch et al, 1986;Erdogdu et al, 1993;Kleihues and Hossmann, 1971) and experimental global cerebral ischemia (Kranse and Tiffany, 1993;Widmann et al, 1991). The latter is partly explained by selective impairment of nuclear-cytoplasmic transport of mRNA, so that while total RNA synthesis is normal during reperfusion, individual mRNA species may be differentially lost (Matsumoto et al, 1990;Sakaguchi et al, 1988).…”

The Intraischemic and Early Reperfusion Changes of Protein Synthesis in the Rat Brain. eIF-2α Kinase Activity and Role of Initiation Factors eIF-2α and eIF-4E

“…Yanagihara (1978), using the model of carotid artery occlusion, noted a 50% decrease of in vitro protein synthesis after 30 minutes of ischemia, and Orunesu et aI., (1980), using a gerbil model of unilateral carotid ligation, showed protein synthesis inhibition after only 5 minutes of ischemia. More recently, Erdogdu et al (1993) have presented evidence of the activation of a translational inhibitor during ischemia using a cell-free system combining intact reticulocyte lysates with ex tracts from individual rat brain regions after four-vessel occlusion.…”

Investigation of Synaptic Tagging/Capture and Cross-capture using Acute Hippocampal Slices from Rodents

“…Hence such variations should be avoided. It has been observed that glutamate receptor-dependent calcium release occurring during the preparation steps can irreversibly affect protein synthesis in nervous tissue 35,36,37 . Using manual tissue slicers can help to minimize this by allowing the process to be completed very quickly as compared to vibraslicers.…”