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Elevated Seizure Threshold and Impaired Spatial Learning in Transgenic Mice with Putrescine Overproduction in the Brain
Author(s) -
Halonen T.,
Sivenius J.,
Miettinen R.,
Halmekytö M.,
Kauppinen R.,
Sinervirta R.,
Alakuijala L.,
Alhonen L.,
MacDonald E.,
Jänne J.,
Riekkinen P. J.
Publication year - 1993
Publication title -
european journal of neuroscience
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.346
H-Index - 206
eISSN - 1460-9568
pISSN - 0953-816X
DOI - 10.1111/j.1460-9568.1993.tb00978.x
Subject(s) - putrescine , genetically modified mouse , transgene , neuroprotection , ornithine decarboxylase , agmatine , hippocampus , polyamine , ornithine , biology , glutamate receptor , striatum , catabolism , medicine , endocrinology , neuroscience , chemistry , dopamine , biochemistry , amino acid , metabolism , gene , enzyme , arginine , receptor
We have studied the role of putrescine by using transgenic mouse lines overexpressing the human ornithine decarboxylase gene in most of their tissues. The aberrant expression of the transgene is most strikingly manifested in the brain, leading to an increase of up to 20‐fold in putrescine content. We report that the transgenic mice with grossly elevated putrescine in all brain regions analysed (cortex, striatum, hippocampus and cerebellum) showed a significantly elevated seizure threshold to chemical and electrical stimuli, and impaired performance in spatial learning and memory tests. The view that putrescine may be primarily responsible for these changes was supported by the fact that the concentrations of the major neurotransmitter amino acids, glutamate and GABA in the brain, were not changed in the transgenic animals, and by the finding that a further increase in brain putrescine, achieved by inhibition of the catabolism of l ‐ornithine, appeared to provide additional protection against electroshock‐induced seizures. These results suggest that the commonly observed increase in ornithine decarboxylase activity and the massive increase in brain putrescine in connection with neuron damage is a neuroprotective measure rather than a cause of the damage.