Cook, T. M., and Crutcher, K. A. (1986). Intrahippocampal injection of kainic acid produces significant pyramidal cell loss in neonatal rats. Neuroscience,18(1):79-92.
Abstract
Previous reports have indicated that pyramidal cells in the
developing rat hippocampal formation are not destroyed by
intraventricular or intraperitoneal administration of kainic acid.
We examined the neurotoxic properties of kainic acid and ibotenic
acid following intrahippocampal injection in neonatal rats and found
significant pyramidal cell death following injection of 1.0
microgram kainic acid in 6, 7 and 9-day-old pups. At doses 2.5 or
five times this amount, significant pyramidal cell loss was obtained
in 5-day-old rats as well. The susceptibility of pyramidal neurons
to kainic acid increased as a function of age. The developing
hippocampus was considerably more vulnerable to ibotenic acid
compared with kainic acid, in contrast to the order of potency
reported in adult rats. The increased sensitivity of CA3 pyramidal
cells parallels the development of the mossy fiber innervation to
the dendrites of these cells supporting the twofold mechanism
suggested by Coyle for kainic acid neurotoxicity; that is, a direct
cytotoxic action via postsynaptic receptors as well as increased
sensitivity due to the presence of excitatory inputs.
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