Culture, characterization and sensitivity to laser and photosensitizers of bovine coronary artery endothelium is presented. Endothelial cells from bovine coronary artery specimens obtained after sacrifice were successfully cultured. Endothelial cells were obtained from the anterior descending coronary artery. Cells were grown in RPMI-1640 with 20% fetal bovine serum. Preconditioned medium was required to enhance the efficiency of the initial inoculum. The resulting cultures could be passed for up to 15 times and maintained a stable, normal karyotype throughout this period. The culture reached a stable confluency packing density by two to three weeks (5 x 10(5) to 10(6) cells/cm2). When cultures were maintained at the confluency packing density for three to four weeks, the cells had the unique tendency to assume capillary-like networks of cell cords around which neighboring cells showed polar orientation and migration towards the apparent tube-like structures without the need for added extracellular matrix. All cultured cells were stained positive with mouse anti-human factor VIII monoclonal antibody tagged with either Texas red-streptavidin or fluorescein isothiocyanate (FITC). All cultures were negative for staining with mouse monoclonal antibody to alpha actin tagged with FITC, suggesting absence of smooth muscle cells or fibroblasts. Cells were negligibly sensitive to argon laser irradiation at wave lengths 620 nm at 37 J/cm2. Cultured cells showed dose dependent sensitivity to both unactivated HPD and phycocyanin with minimal cytotoxicity (less than 20%) at concentrations below 0.5 and 50 micrograms/ml, respectively. Laser activation of the photosensitizers at these concentrations resulted in similar but significant cell death, 40% and 41% respectively.(ABSTRACT TRUNCATED AT 250 WORDS)