Hunziker M, et al. - An inspection was performed of the platelet-derived growth factor receptor alpha-positive cells (PDGFRα+), in terms of the human ureteropelvic junction (UPJ). The findings illustrated the PDGFR&alpha+ cell expression in the human UPJ. Altered small conductance Ca2+-activated K+ (SK3) channel expression observed in PDGFRα+ cells in UPJ obstruction was indicative of the impairment of SK3 activity across the UPJ possibly disturbing the upper urinary tract peristalsis in this urological condition.