title: Electric pulse stimulation induces NMDA glutamate receptor mRNA in NIH3T3 mouse fibroblasts.
abstract: Excess glutamate and Ca(2+) influx into neurons exacerbate brain damage such as ischemia. Astrocytes at the site of damage proliferate and attenuate the glutamate- and Ca(2+)-induced neuronal damage by removing excess glutamate and Ca(2+) through the N-methyl-D-aspartate (NMDA) glutamate receptor and the L-type Ca(2+) channel, respectively. Fibroblasts are commonly mobilized to the site of damage, probably supporting the restoration process. Notably, fibroblasts express the L-type voltage-sensitive Ca(2+) channel, but not central nervous system-specific NMDA glutamate receptor. We examined if electric pulse stimulation (EPS) was capable of inducing NMDA receptor on fibroblasts by way of Ca(2+) channel activation, so that they could potentially have a neuroprotective role. To activate L-type Ca(2+) channel, we delivered electric pulse to cultured NIH3T3 mouse fibroblasts. EPS of 20 V with a pulse duration of 2 msec at a frequency of 1 Hz for more than 1 h up to 24 h successfully introduced Ca(2+) into NIH3T3 fibroblasts as detected by Fluo-4AM calcium imaging, which was totally inhibited by a L-type Ca(2+) channel inhibitor, verapamil. Remarkable expression of NMDA receptor mRNA in the fibroblasts after 24-h EPS was demonstrated by RT-PCR. Verapamil treatment during EPS totally abrogated the EPS-induced NMDA receptor mRNA expression. To the best of our knowledge, this is the first report showing that electric pulse is able to induce sustained Ca(2+) influx via L-type Ca(2+) channel in a non-excitatory fibroblast, which leads to the expression CNS-specific NMDA receptor mRNA. Neuroprotective role of NMDA receptor induced in fibroblasts needs to be further examined.
authors.affiliation: Department of Medicine and Science in Sports and Exercise, Tohoku University Graduate School of Medicine, Sendai, Japan.
authors.forename: Saeko
authors.initials: S
authors.lastname: Okutsu
authors.forename: Hiroyasu
authors.initials: H
authors.lastname: Hatakeyama
authors.forename: Makoto
authors.initials: M
authors.lastname: Kanzaki
authors.forename: Makoto
authors.initials: M
authors.lastname: Kanazaki
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Tsubokawa
authors.forename: Ryoichi
authors.initials: R
authors.lastname: Nagatomi
mesh_terms: D000814:Aniline Compounds / Q000378:metabolism; D000818:Animals; D002118:Calcium / Q000378:metabolism; D002121:Calcium Channel Blockers / Q000494:pharmacology; D020746:Calcium Channels, L-Type / Q000378:metabolism; D002478:Cells, Cultured; D002614:Chelating Agents / Q000494:pharmacology; D004533:Egtazic Acid / Q000031:analogs & derivatives / Q000494:pharmacology; D004558:Electric Stimulation / Q000379:methods; D005347:Fibroblasts / Q000378:metabolism*; D005456:Fluorescent Dyes / Q000378:metabolism; D018698:Glutamic Acid / Q000494:pharmacology; D008297:Male; D051379:Mice; D041681:NIH 3T3 Cells; D012333:RNA, Messenger / Q000378:metabolism*; D016194:Receptors, N-Methyl-D-Aspartate / Q000378:metabolism*; D014700:Verapamil / Q000494:pharmacology; D014966:Xanthenes / Q000378:metabolism
chemical_list: D000814:Aniline Compounds; D002121:Calcium Channel Blockers; D020746:Calcium Channels, L-Type; D002614:Chelating Agents; C409648:Fluo 4; D005456:Fluorescent Dyes; D012333:RNA, Messenger; D016194:Receptors, N-Methyl-D-Aspartate; D014966:Xanthenes; D018698:Glutamic Acid; D004533:Egtazic Acid; D014700:Verapamil; C025603:1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid; D002118:Calcium