title: Upregulation of vascular endothelial growth factor receptors Flt-1 and Flk-1 in rat hippocampus after transient forebrain ischemia.
abstract: This study characterizes the distribution of the two tyrosine kinase receptors for vascular endothelial growth factor (VEGF), Flt-1 and Flk-1, in the rat hippocampus following transient forebrain ischemia. The semi-quantitative reverse transcriptase-polymerase chain reaction (RT-PCR) analysis of Flt-1 and Flk-1 in hippocampal CA1 showed upregulation of these receptors following ischemic injury. Expression of Flt-1 and Flk-1 mRNA was restricted to neurons in the pyramidal cell and granule cell layers in control animals; however, upregulation was detected in activated glial cells and in the vascular endothelial cells rather than in neurons, in ischemic hippocampi. Most of the activated glial cells expressing Flt-1 and Flk-1 were reactive astrocytes, although some were microglial cells. The spatiotemporal expression of Flt-1 in the ischemic hippocampus mirrored that of Flk-1 expression. Expression of mRNA for both receptors was induced after 12 h, appeared to be increased progressively until 3 days when the highest expression was reached, and was sustained for more than 2 weeks. Flt-1 and Flk-1 immunoreactivity in the ischemic hippocampus matched the mRNA induction patterns except for a somewhat delayed onset. These data suggest that VEGF may be involved in the glial response via specific VEGF receptors in the rat hippocampus following transient forebrain ischemia.
authors.affiliation: Department of Anatomy, College of Medicine, Catholic University of Korea, Seoul, Korea.
authors.forename: Jeong-Sun
authors.initials: JS
authors.lastname: Choi
authors.forename: Ha-Young
authors.initials: HY
authors.lastname: Kim
authors.forename: Jung-Ho
authors.initials: JH
authors.lastname: Cha
authors.forename: Jae-Youn
authors.initials: JY
authors.lastname: Choi
authors.forename: Myung-Hoon
authors.initials: MH
authors.lastname: Chun
authors.forename: Mun-Yong
authors.initials: MY
authors.lastname: Lee
mesh_terms: D000818:Animals; D006624:Hippocampus / Q000378:metabolism*; D007150:Immunohistochemistry; D017403:In Situ Hybridization; D002546:Ischemic Attack, Transient / Q000378:metabolism*; D008297:Male; D009419:Nerve Tissue Proteins / Q000096:biosynthesis; D012333:RNA, Messenger / Q000096:biosynthesis / Q000235:genetics; D051381:Rats; D017207:Rats, Sprague-Dawley; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015854:Up-Regulation; D040281:Vascular Endothelial Growth Factor Receptor-1 / Q000096:biosynthesis*; D040301:Vascular Endothelial Growth Factor Receptor-2 / Q000096:biosynthesis*
chemical_list: D009419:Nerve Tissue Proteins; D012333:RNA, Messenger; D040281:Vascular Endothelial Growth Factor Receptor-1; D040301:Vascular Endothelial Growth Factor Receptor-2