RESUMO
Objective To investigate the effect of docosahexaenoic acid (DHA) on Ca2+ mobilization in a neuroendocrine cell line PC12 transfected with rat GPR40 gene and explore the possible mechanisms. Methods The vector containing rat GPR40 gene was constructed and wansfected into naive PC12 cells, in which the stable expressions of GPR40 mRNA and protein were detected using RT-PCR and Western blotting, respectively. In the media of the naive PC12 cells, empty vector-transfected cells and GPR40 vector-transfected cells, DHA was added at the concentration of 10 μmol/L and the intracellular Ca2+ concenWation of the cells was detected. Results No significant changes were found in the inwacellular Ca2+ concentration of the naive or empty vector-transfected PC12 cells after DHA treatment. In the cells transfected with rat GPR40 gene, the intracellular Ca2+ concentration increased rapidly in response to DHA treatment regardless of the extracellular Ca2+ concentration, Intracellular Ca2+ concentration in cells transfected with rat GPR40 gone and added Xestospongin C had no significant chang. Conclusion DHA can modulate Ca2+ mobilization in PC12 cells transfected with GPR40 gone, and this effect can be inhibited by Xestospongin C, indicating that DHA may improve the neurological functions by mobilizing intracellular Ca2+ through the GPR40 signaling pathway.
RESUMO
Objective To investigate the expression of free fatty acid receptor GPR40 and evaluate the possible function of GPR40 in the adult monkey hippocampus after ischemia. Methods According to the post-ischemic adult monkey model of Yamashima, a total of 24 adult monkeys were randomly divided into 4 groups: sham-operated group (control) and post-ischemic day 4, 9, 15 (d4, d9,d15). The expression of free fatty acid receptor GPR40 was detected at the protein level by immunoblotting and immunohistochemistry in the adult monkey hippocampus. Results Immunoblotting analysis showed the expression of GPR40 was decreased in CA1 and increased in DG after ischemia (posfischemic group vs control, P＞0.05). Immunohistochemistry data revealed that the double stained cells of GPR40 and NeuN were also decreased by 50% (d15) in CA1 and had no significant changes in DG after ischemia. Interestingly, the co-labeled cells of GPR40 and GFAP were increased 2.5 folds (d4) in post-ischemic SGZ. Conclusions There is the different expression of GPR40 in adult monkey hippocampal CA1 and DG regions after ischemia. Co-labeled cells of GPR40 and GFAP are increased in post-ischemic SGZ, which indicates that polyunsaturated free fatty acid such as DHA, a ligand of GPR40, may alleviate neuronal injury in post-ischemic hippocampus.