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Homocysteine-induced vascular dysregulation is mediated by the NMDA receptor

Homocysteine-induced vascular dysregulation is mediated by the NMDA receptor VASCULAR MEDICINE Qureshi, I., Chen, H. J., Brown, A. T., Fitzgerald, R., Zhang, X. J., Breckenridge, J., Kazi, R., Crocker, A. J., Stuhlinger, M. C., Lin, K., Cooke, J. P., Eidt, J. F., Moursi, M. M. 2005; 10 (3): 215-223

Abstract

Elevated plasma homocysteine accelerates myointimal hyperplasia and luminal narrowing after carotid endarterectomy. N-methyl D aspartate receptors (NMDAr) in rat cerebrovascular cells are involved in homocysteine uptake and receptor-mediated stimulation. In the vasculature, NMDAr subunits (NR1, 2A-2D) have been identified by sequence homology in rat aortic endothelial cells. Exposure of these cells to homocysteine increased expression of receptor subunits, an effect that was attenuated by dizocilpine (MK801), a noncompetitive NMDA inhibitor. The objective of this study was to investigate the existence of an NMDAr in rat vascular smooth muscle (A7r5) cells, and also the effect of homocysteine on vascular dysregulation as mediated by this receptor. Subunits of the NMDAr (NR1, 2A-2D) were detected in the A7r5 cells by using the reverse transcriptase polymerase chain reaction and Western blotting. Homocysteine induced an increase in A7r5 cell proliferation, which was blocked by MK801. Homocysteine, in a dose and time dependent manner, increased expression of matrix metallinoproteinase-9 and interleukin-1beta, which have been implicated in vascular smooth muscle cell migration and/or proliferation. Homocysteine reduced the vascular elaboration of nitric oxide and increased the elaboration of the nitric oxide synthase inhibitor, asymmetric dimethylarginine. All of these homocysteine mediated effects were inhibited by MK801. NMDAr exist in vascular smooth muscle cells and appear to mediate, at least in part, homocysteine-induced dysregulation of vascular smooth muscle cell functions.

View details for DOI 10.1191/1358863x05vm626oa

View details for Web of Science ID 000232556600006

View details for PubMedID 16235775