The effect of iron overload on spatial memory and acetylcholine receptor expression in the hippocampus of rats (907.8)

Abstract

Title: Effect of iron overload on spatial memory and acetylcholine receptor expression in the hippocampus of rats Department of Pharmaceutical Sciences, Northeastern University, Boston, MA, USA Author: Murui Han, Jonghan Kim Iron plays an essential role in cognition and memory. While iron deficiency is associated with reduced memory capacity, we have previously demonstrated that iron overload improved a recognition memory performance in growing rats. We here characterized the effect of iron overload on special memory and explored molecular mechanisms involved in memory. Barnes maze test was conducted using rats fed iron overload diet (10,000 mg iron/kg diet) or control diet (50 mg/kg) for 4 weeks. Compared with controls, iron overload (IO) rats spent less time (57% decrease; p<0.001) and poked less errors (13% decrease; p=0.042) to find the target hole during the first training day (n=8/group), which indicates a better spatial memory upon iron loading. Western blotting was employed to examine memory‐related proteins in the hippocampus. IO rats up‐regulated nicotinic acetylcholine receptor alpha‐7 (nAChR; p=0.045; n=3‐4/group). Activities of superoxide dismutase (anti‐oxidant enzyme) or levels of malondialdehyde (lipid peroxidation marker) were not altered in IO rats. In addition, ICP‐MS results showed that brain metal levels (iron, zinc, manganese) were not altered in IO rats, indicating no evidence that IO promotes oxidative stress. Collectively, increasing memory performance under iron loading in growing rats could be due to up‐regulation of nAChR with brain metals unaffected. Supported by NIH R00 ES017781.Grant Funding Source: NIH R00 ES017781