66 M. Desforges and others J Physiol 587.1 Figure 1. Immunolocalization of SNAT1, SNAT2 and SNAT4 in ﬁrst trimester and term placentas Representative photomicrographs for SNAT1 in ﬁrst trimester (A–C) and term placenta (D–E). Immunostaining is predominantly in trophoblast cells (cytotrophoblast cells: CT and the syncytiotrophoblast: ST), with heterogeneous intense staining on the microvillous membrane (MVM) (A and D). Additional staining was present in stromal Hofbauer cells (asterisks) and vascular endothelium (V) in ﬁrst trimester (B and C), but not term (E inset), placenta. SNAT2 exhibited a similar immunostaining pattern in ﬁrst trimester (G–I) and term (J–L) placenta, but with endothelial staining present in vessels throughout pregnancy (H and L). Representative images for SNAT4 immunohistochemistry in ﬁrst trimester (M–O) and term (P–R) placenta, illustrate a similar localization. Immuno- staining is predominantly syncytial, with MVM staining more pronounced in ﬁrst trimester (M) than term (P). Negative controls are shown in F, I and R. Scale bars represent 50 μm; scale bar on image A refers to all images, except image O. C 2009 The Authors. Journal compilation C 2009 The Physiological Society