Levels of mRNA for c-fos, nerve growth factor (NGF), brain-derived neurotrophic factor (BDNF), neurotrophin-3 (NT-3), TrkB, and TrkC were studied using in situ hybridization in the rat brain at different reperfusion times after unilateral middle cerebral artery occlusion (MCAO). Short-term (15 min) MCAO, which does not cause neuronal death, induced elevated BDNF mRNA expression confined to ipsilateral frontal and cingulate cortices outside the ischemic area. With a longer duration of MCAO (2 h), which leads to cortical infarction, the increase was more marked and elevated BDNF mRNA levels were also detected bilaterally in dentate granule cells and CA1 and CA3 pyramidal neurons. Maximum expression was found after 2 h of reperfusion. At 24 h BDNF mRNA expression had returned to control values. In the ischemic core of the parietal cortex only scattered neurons were expressing high levels of BDNF mRNA after 15 min and 2 h of MCAO. Analysis of different BDNF transcripts showed that MCAO induced a marked increase of exon III mRNA but only small increases of exon I and II mRNAs in cortex and hippocampus. In contrast to BDNF mRNA, elevated expression of c-fos mRNA was observed in the entire ipsilateral cerebral cortex, including the ischemic core, after both 15 min and 2 h of MCAO. Two hours of MCAO also induced transient, bilateral increases of NGF and TrkB mRNA levels and a decrease of NT-3 mRNA expression, confined to dentate granule cells. The upregulation of BDNF mRNA expression in cortical neurons after MCAO is probably triggered by glutamate through a spreading depression-like mechanism. The lack of response of the BDNF gene in the ischemic core may be due to suppression of signal transduction or transcription factor synthesis caused by the ischemia. The observed pattern of gene expression after MCAO agrees well with a neuroprotective role of BDNF in cortical neurons. However, elevated levels of NGF and BDNF protein could also increase synaptic efficacy in the postischemic phase, which may promote epileptogenesis.
Experimental Neurology – Elsevier
Published: Nov 1, 1995
It’s your single place to instantly
discover and read the research
that matters to you.
Enjoy affordable access to
over 18 million articles from more than
15,000 peer-reviewed journals.
All for just $49/month
Query the DeepDyve database, plus search all of PubMed and Google Scholar seamlessly
Save any article or search result from DeepDyve, PubMed, and Google Scholar... all in one place.
Get unlimited, online access to over 18 million full-text articles from more than 15,000 scientific journals.
Read from thousands of the leading scholarly journals from SpringerNature, Elsevier, Wiley-Blackwell, Oxford University Press and more.
All the latest content is available, no embargo periods.
“Hi guys, I cannot tell you how much I love this resource. Incredible. I really believe you've hit the nail on the head with this site in regards to solving the research-purchase issue.”Daniel C.
“Whoa! It’s like Spotify but for academic articles.”@Phil_Robichaud
“I must say, @deepdyve is a fabulous solution to the independent researcher's problem of #access to #information.”@deepthiw
“My last article couldn't be possible without the platform @deepdyve that makes journal papers cheaper.”@JoseServera