Axon Guidance of Sympathetic Neurons to Cardiomyocytes by Glial Cell Line-Derived Neurotrophic Factor (GDNF)
Figure 3
Expression of β1-adrenergic receptors in sympathetic neurons adjacent to VMs.
Proximity co-cultures of GFP-knocked-in VMs and SNs (5 days) were immunolabeled for neurofilament-M (NFM, blue) and β1-adrenergic receptors (BAR; red). A) Representative fluorescence images of co-cultures treated with vehicle only were used as controls (CONT, top), treated with GDNF 10 ng/ml (middle) and treated with NGF 50 ng/ml (bottom). Pictures from left to right are labeled for GFP+NFM, NFM+BAR, GFP+BAR, and GFP+NFM+BAR. The immunopositive domains for BAR, which are most abundant with GDNF, are recognized on the surface membrane of VMs in contact with axons from SNs; the overlapping is colored by orange (GFP+BAR) or purple (NFM+BAR). B) Treatment with GDNF in co-cultures also leads to nuclear or perinuclear expression of BAR in VMs (white arrow heads). C) The density of immunopositive BAR distributing on VMs (GFP-positive area). Values are means+SD of 4 co-cultures in each group. *Significantly different from control at p<0.05. #Significantly different from co-cultures treated with NGF at p<0.05. Bars indicate 20 µm.