Dual mechanisms of Ca2+ increases elicited by N-methyl-D-aspartate in immature and mature cultured cortical neurons

✍ Scribed by Noritaka Nakamichi; Hiroshi Ohno; Nobuyuki Kuramoto; Yukio Yoneda

• Book ID: 102380441
• Publisher: John Wiley and Sons
• Year: 2001
• Tongue: English
• Weight: 395 KB
• Volume: 67
• Category: Article
• ISSN: 0360-4012
• DOI: 10.1002/jnr.10096

✦ Synopsis

Abstract

Cortical primary cultures were loaded with the fluorescent indicator fluo‐3 for assessment of intracellular‐free Ca^2+^ ions with the aid of a confocal laser‐scanning microscope. The addition of N‐methyl‐D‐aspartic acid (NMDA) markedly increased the number of fluorescent cells in a manner sensitive to prevention by both an NMDA channel blocker and MgCl~2~. In the absence of added MgCl~2~, NMDA induced a sustained increase in the number of fluorescent cells with a transient increase by KCl in cells cultured for 3 days in vitro (DIV). Both nifedipine and dantrolene were more potent in preventing the increase by NMDA in cortical preparations cultured for 9 DIV than those for 3 DIV. These results suggest that activation of NMDA receptors may lead to a sustained increase in intracellular‐free Ca^2+^ concentrations in immature cultured neurons, in a manner less dependent on the influx through L‐type voltage‐dependent channels as well as the release from intracellular stores than in mature neurons. © 2001 Wiley‐Liss, Inc.