A drug used to increase blood production in both medical treatments and athletic
doping scandals seems also to improve memory in those using it. New research
published in the open access journal
BMC Biology shows that the memory
enhancing effects of erythropoietin (EPO) are not related to its effects on
blood production but due to direct influences on neurons in the brain. The
findings may prove useful in the treatment of diseases affecting brain function,
such as schizophrenia, multiple sclerosis, and Alzheimer's.
Patients
given EPO to treat chronic kidney failure had been observed to have improved
cognition after starting the drug. "These effects of EPO were thought to result
from the blood-boosting effects of the drug", explains Hannelore Ehrenreich at
the Max Planck Institute, "but the finding of receptors for EPO on nerve cells
in the brain suggests that some other mechanism might be involved."
To
investigate the mechanisms of EPO-enhanced cognition, the researchers injected
mice with EPO every other day for three weeks (11 doses) to test the effects of
long-term exposure. After the treatment period, mice given EPO had better memory
in some situations than did mice that had been given a placebo instead. The
improvement in memory lasted up to three weeks from the last EPO dose and
outlasted increased blood-cell production, but had disappeared by four weeks.
Mice given three doses saw no benefit with respect to memory improvement.
"Young mice systematically treated with EPO for three weeks have
improved memory, similar to the dramatic improvements observed in endurance and
muscular performance athletes who use EPO to boost performance", says
Ehrenreich. The specific memory improvements were associated with the
hippocampus, a structure in the brain involved in learning and memory, among
other functions.
The researchers did a series of experiments on
hippocampal tissue taken from the mice and found that EPO directly affected the
neurons in this structure. "EPO had pronounced effects on short-term and
long-term plasticity in the hippocampus as well as on synaptic transmission",
the researchers report. "Treatment with EPO seems to increase the number of
inhibitory circuits, which actually increases the efficiency of transmission of
excitatory nerve impulses in specific neurons, resulting in greater short-term
and long-term plasticity in memory pathways in the hippocampus."
These
findings begin to shed light on the mechanisms of improvements in cognition seen
in patients with schizophrenia and multiple sclerosis as a result of treatment
with this drug. As well as working to refine these findings, further studies
might also investigate the effects of EPO on other brain regions that might be
associated with improvements in motor functions in multiple sclerosis, and
investigate the potential of using EPO or targeting the networks involved in
EPO-generated neuronal plasticity in the treatment of neurodegenerative
diseases.
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Article adapted by Medical
News Today from original press release.----------------------------
Notes: 1. Erythropoietin enhances hippocampal long-term
potentiation and memory
Bartosz Adamcio, Derya Sargin, Alicja Stradomska,
Lucian Medrihan, Christoph Gertler, Fabian Theis, Mingyue Zhang, Michael Müller,
Imam Hassouna, Kathrin Hannke, Swetlana Sperling, Konstantin Radyushkin, Ahmed
El-Kordi, Lizzy Schulze, Anja Ronnenberg, Fred Wolf, Nils Brose, Jeong-Seop
Rhee, Weiqi Zhang and Hannelore Ehrenreich
BMC Biology (in press)
Article available at the journal website:
http://www.biomedcentral.com/bmcbiol/ All articles are
available free of charge, according to BioMed Central's open access policy.
2. BMC Biology - the flagship biology journal of the BMC series -
publishes open access research and methodology articles of special importance
and broad interest in any area of biology and biomedical sciences.
BMC
Biology (ISSN 1741-7007) is covered by PubMed, MEDLINE, BIOSIS, CAS, Scopus,
EMBASE, Zoological Record, Thomson Scientific (ISI) and Google Scholar. The
journal will receive its first Impact Factor in 2008.
BMC Biology has an
Impact Factor of 5.06.
3. BioMed Central (
http://www.biomedcentral.com/) is an independent online
publishing house committed to providing immediate access without charge to the
peer-reviewed biological and medical research it publishes. This commitment is
based on the view that open access to research is essential to the rapid and
efficient communication of science.
Source: Charlotte Webber
BioMed
Central
