Abstract: For the past decade, estrogen actions rapid in onset, short in duration through the putative membrane estrogen receptor have attracted considerable attention. Nevertheless, there is so far limited evidence for estrogenic nongenomic regulation of the adenyl cyclase-cAMP-PKA system, especially in the brain. The present study reconfirms that 17beta-estradiol induces membrane-mediated PKA activation with a short latency in a living hippocampal neural cell with use of BSA-conjugated beta-estradiol which does not reach the nuclear estrogen receptor following my previous publication.
Abstract: To study nicotine's effects on neurogenesis in the dentate gyrus of the hippocampus, nicotine was injected intraperitoneally into adult rats. After sacrificing, the hippocampal formation was processed for immunohistochemical staining of PSA-NCAM, NeuN and GFAP. Nicotine decreased numbers of PSA-NCAM(+) and NeuN(+) cells dose-dependently.
Abstract: The basic mechanisms of nerve protection by estrogen remain to be clarified. This study was undertaken to confirm estrogen-induced insulin-like growth factor 1 (IGF-1) mRNA expression in the immortalized rat hippocampal cell H19-7 using a real-time quantitative polymerase chain reaction (PCR) assay, which has considerably increased accuracy and rapidity over other current methods. Upon stimulation by estradiol, the copy number of ERalpha mRNA showed a 1.4-fold increase, and that of IGF-1 mRNA showed a 38.5-fold increase when compared with the control value. ICI182,780 inhibited the estradiol-induced upregulation of ERalpha mRNA completely, while it inhibited estradiol-stimulated IGF-1 mRNA expression partially. The increase of the copy number of IGF-1 mRNA was accomanied by enhancement of IGF-1 protein as observed by Western blot analysis.
Abstract: 17beta-estradiol-stimulated PKA activation in living differentiated H19-7 cells was visualized using DR2, a cell-permeable fluorescent PKA substrate. Estradiol induced marked changes of fluorescence in cytosolic areas and these were inhibited by a PKA inhibitor.
Abstract: General injection of nicotine induced an immediate and marked inhibition of estrogen response element (ERE) binding in the rat brain. Either mecamylamine or nifedipine fully antagonized the ERE binding-inhibiting effect of nicotine.
