Stromal-cell contractility is known to play an important role in the development of bladder outlet obstruction secondary to benign prostatic hyperplasia (BPH). An in vitro model of single-cell contraction was developed to investigate the effect of alpha1-adrenoceptor agonists and antagonists. Human prostatic stromal cells were isolated from prostatectomy and cystoprostatectomy specimens. The cells were cultured in a selective medium supplemented with growth factors and steroid hormones. The culture flasks were coated with a viscous agent to allow cell contraction. Contractions were visualized by means of a cell-culture microscope fitted with a time-lapse video system. For quantitative analysis, the percentage of contracting cells was evaluated. Nineteen percent of the cells were found to contract without stimulation. Following incubation with doxazosin (10 nM, 100 nM, and 1 mM), there was a slight dose-dependent decrease in the number of spontaneously contracting cells, whereas adrenergic stimulation using 10 microM of phenylephrine led to a significant increase in the percentage of contracting cells (55%). Following incubation with 100 nM of doxazosin, the phenylephrine-induced effect was significantly reduced. This simple in vitro model of cell contraction in the prostate provides a useful means of investigating drug effects on prostatic stromal cells.