['Human detrusor smooth muscle cells (hBSMCs) are coupled by connexin 43 (Cx43)-positive gap junctions to form functional syncytia. Gap junctional communication likely is necessary for synchronised detrusor contractions and is supposed to be altered in voiding disturbances. Other authors have shown that the pleiotropic cytokine TGF-beta1 upregulates Cx43 expression in human aortic smooth muscle cells.', 'In this study, we examined the TGF-beta1 effects on Cx43 expression in cultured hBSMCs.', 'hBSMC cultures, established from patients undergoing cystectomy, were treated with recombinant human TGF-beta1.', 'Cx43 expression was then examined by Western blotting, real-time PCR, and immunocytochemistry. Dye-injection experiments were used to study the size of functional syncytia.'] Does tGF-beta1 inhibit Cx43 expression and formation of functional syncytia in cultured smooth muscle cells from human detrusor?