“…As summarized in Figure 3 , there is evidence showing that all adrenergic receptor subtypes are expressed in the human fetoplacental vasculature. The majority of studies have been conducted using HUVECs or whole placental homogenates, and reported the expression of α 1A , α 1B , α 1D , α 2A , α 2B , α 2C [ 58 , 63 , 69 , 70 ] and β 1 , β 2 and β 3 adrenergic receptor subtypes [ 58 , 73 , 74 , 76 , 79 ], without clarifying the locus or the vessel type [ 70 , 73 , 74 , 76 ] and with a likely high background expression from trophoblast cells [ 69 ]. α 2A appears to be the only adrenergic receptor subtype identified in both endothelial cells and VSMCs within the blood vessels of stem, intermediate and terminal villi [ 69 ].…”