Effects of All-trans Retinoic Acid on Intracellular Calcium Concentration of Hippocampal Neurons

Abstract: To investigate the effects and possible mechanisms of all-trans retinoic acid (atRA) on the intracellular Ca2+ level of primary cultured hippocampal neurons. Hippocampal cells were isolated from newborn rats within 24 hours and cultured for 1?2 days prior to experiments. Immunofluorescence was performed to evaluate the purity of cultured cells.The cultured primary hippocampal neurons were labeled with fura-2/AM， and fluorescence images were monitored using a CCD camera， and subsequently analyzed using imaging analyzing software. Ca2+ activities were presented as Ratio 340/380， the ratio of fluorescence intensities excited by alternating illumination of 340 nm and 380 nm beams. We showed that atRA caused an increase in the intracellular calcium concentration in primary hippocampal neurons， which was related with concentrations of atRA and days of neurons in vitro (DIV). Furthermore， the increase in calcium level caused by atRA was through influx of extracellular calcium. Finally， we found that Ro41-5253 (Ro) reduced the increased Ratio 340/380 of hippocampal neurons caused by atRA. This study suggests that atRA can modulate calcium influx in hippocampal neurons， which was related with concentrations of atRA and days of neurons in vitro. AtRA plays a role in modulating calcium levels in hippocampal neurons possibly by binding to RARa. Finally， the role of atRA in regulating calcium concentration might be related to its effect on long-term potentiation (LTP)， learning， and memory.

CSTR: 32200.14.cjcb.2010.02.0013