Kainic acid induces leukemia inhibitory factor mRNA expression in the rat brain: differences in the time course of mRNA expression between the dentate gyrus and hippocampal CA1/CA3 subfields.
Leukemia inhibitory factor (LIF) is a pluripotent cytokine which affects the survival and differentiation of various types of cells both in the hematopoietic and nervous systems. In this study, the time course and localization of LIF mRNA expression following kainic acid-induced seizures were examined by northern blot analyses and in situ hybridization. Northern blot analyses demonstrated that intraperitoneal injection of kainic acid at a convulsive dose induced LIF mRNA expression intensely in the hippocampus and moderately to weakly in the cerebral cortex, thalamus and hypothalamus. The expression peaked at 8-24 h after the injection in the hippocampus and cerebral cortex and at 8 h in the thalamus and hypothalamus. In situ hybridization revealed different time courses of LIF mRNA expression depending on the area of the hippocampus; that is, the expression peaked at 10 h in the granule cell layer of the dentate gyrus, then at 12 h in the polymorph and molecular layers of the dentate gyrus, and finally at 12-24 h in the strata oriens and radiatum of the CA1 and CA3 subfields. It is worth noting that the expression of LIF mRNA was intense in the dentate gyrus, the region where neurogenesis and aberrant network reorganization have been shown to be induced by seizures. The upregulation of LIF mRNA expression in the dentate granule cell layer followed by that in the dentate polymorph and molecular layers may be involved in activity-dependent neurogenesis in the granule cell layer and ectopic migration of granule cells to the polymorph and molecular layers in the dentate gyrus.
Minami
Masabumi
M
Department of Molecular Pharmacology, Faculty of Pharmaceutical Sciences, Kyoto University, Kyoto 606-8501, Japan.
Maekawa
Keiko
K
Yamakuni
Hisashi
H
Katayama
Takahiro
T
Nakamura
Junji
J
Satoh
Masamichi
M
D000818:Animals; D002454:Cell Differentiation / Q000187:drug effects / Q000235:genetics; D002455:Cell Division / Q000187:drug effects / Q000235:genetics; D002465:Cell Movement / Q000187:drug effects / Q000235:genetics; D018891:Dentate Gyrus / Q000187:drug effects / Q000254:growth & development / Q000378:metabolism*; D018690:Excitatory Amino Acid Agonists / Q000494:pharmacology; D005786:Gene Expression Regulation / Q000187:drug effects / Q000502:physiology; D006131:Growth Inhibitors / Q000235:genetics*; D006624:Hippocampus / Q000187:drug effects / Q000254:growth & development / Q000378:metabolism*; D015850:Interleukin-6; D007608:Kainic Acid / Q000494:pharmacology; D053605:Leukemia Inhibitory Factor; D008222:Lymphokines / Q000235:genetics*; D008297:Male; D009474:Neurons / Q000187:drug effects / Q000378:metabolism*; D012333:RNA, Messenger / Q000187:drug effects / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D012640:Seizures / Q000139:chemically induced / Q000378:metabolism* / Q000503:physiopathology; D013997:Time Factors; D015854:Up-Regulation / Q000187:drug effects / Q000235:genetics*
D018690:Excitatory Amino Acid Agonists; D006131:Growth Inhibitors; D015850:Interleukin-6; D053605:Leukemia Inhibitory Factor; D008222:Lymphokines; D012333:RNA, Messenger; D007608:Kainic Acid