Hippocampal Glucose Transporter Immunoreactivity after LiPC Induced Status Epilepticus
Abstract number :
2.057
Submission category :
Year :
2001
Submission ID :
3068
Source :
www.aesnet.org
Presentation date :
12/1/2001 12:00:00 AM
Published date :
Dec 1, 2001, 06:00 AM
Authors :
D. Shin, Pediatrics & Research, UCLA & VA GLAHS, GLA, CA; L.G. Mazarati, MD, Pediatrics & Research, UCLA & VA GLAHS, GLA, CA; R. Sankar, MD, PhD, Pediatrics, UCLA, Los Angeles, CA; S. Thamotharan, BVSc, Pediatrics, UCLA, Los Angeles, CA; K. Moley, MD, OBG
RATIONALE: We have previously demonstrated that lithium-pilocarpine(LiPC) status epilepticus(SE) results in neuronal injury in an age dependent manner with maximal CA1 damage in a 2-wk old pup and minimal damage in the hilus. Adult animals, on the other hand, show the opposite pattern. Here we examine whether the increased energy demands from several hours of SE in this model result in acute changes to the hippocampal distribution of well known glucose transporters, GLUT 3 and GLUT 4, as well as to the more recently identified GLUT 8.
METHODS: 2-wk old and adult rats were given lithium chloride followed 20hr later with pilocarpine to induce SE. The rats were perfused with 4% paraformaldehyde and processed for immunohistochemical localization of GLUT 3,GLUT 4 and GLUT 8 in the hippocampus.
RESULTS: In 2-wk old animals, GLUT 3 like immunoreactivity(IR) was seen in the inner molecular layer(IML), stratum oriens and hilus. Following SE, increased diffuse GLUT 3-IR was visible in the hilus. In the adult animals, however, GLUT 3-IR was visible in the CA4 cells/mossy fibers(MF) and extended into the stratum lacunosum which did not change after SE. GLUT 4 immunohistochemistry did not reveal discernible changes in the hippocampus after SE, showing few processes labeled in the hilar/inner granule cell border in 2-wk old pups. In adult rats, GLUT 4-IR was seen in CA1 and CA3 regions which increased slightly after treatment in CA1 and also became visible in the IML. GLUT 8-IR, meanwhile, was visible in the CA4/MF area of 2-wk old pups and appeared in the CA1 and CA3 regions as well after SE. Adult rats showed incresed staining of this novel transporter in the MF as well as in the CA1 and CA3 regions.
CONCLUSIONS: Our data suggest that GLUT 4, the predominant insulin responsive transporter, plays a minimal part in coping with the increased metabolic demand during SE. GLUT 3, meanwhile, may play a more important role for the immature brain during SE; in particular, to help protect against cell injury in the hilus. Lastly, GLUT 8 is responsive at all ages although the consequences of region specific changes are still unclear.
Support: Supported by NS01792 and the DAKO Foundation (RS) and NIH grants HD 33997 and HD 25024 (SUD).