Figure 8. Selective stimulation of GPCR induced Bdnf-eIV mRNA expression through the Ca2+/CN pathway. A–D, Effects of APV (A, C) or FK506 (B, D) on SKF38393-, isoproterenol-, CRF-, or neurotensin-induced Bdnf-eIV mRNA expression. SKF38393 (A, B, 1 μm), isoproterenol (A, B, 10 μm), CRF (C, D, 10 nm), or neurotensin (C, D, 1 nm) was added to cortical cells at 5 d in culture. Total RNA was extracted 1 h later for quantitative RT-PCR. Data represent the mean ± SE (n = 3–5). **p < 0.01 versus control; ##p < 0.01 versus the same sample without inhibitors. We investigated the expression levels of GPCRs in primary cultures of rat cortical cells and found that D1R (Gαs), β1AR (Gαs), CRF receptor 1 (Gαs), and neurotensin receptor 1 (Gαq) were expressed functionally (our unpublished observations). E, The subcellular localization of CRTC1 in cultured cortical cells. Cells were treated with SKF38393, isoproterenol, CRF, or neurotensin for 15 min, and immunostaining was subsequently performed. APV or FK506 was added 10 min before the treatment. Scale bars, 20 μm.