Glomemlar mesangial cells are considered to be modified smooth muscle cells and seem to play a role in the maintenance of glomemlar hemodynamics. The present study was carried out to determine the effect of opioids on adhesiveness, spreading and migration of mesangial cells. Morphine enhanced spreading of mesangial cells at early time periods (5 min, control 8 ± 2% vs. morphine 15+1%, p < 0.05; 15 min, control 21 ± 5% vs. morphine 38 ± 2%, p < 0.05) as well as at later time periods when compared to control cells (at 2 h, control 23 ± 1% vs. morphine 49+1%, p < 0.001; at 3 h, control 28 ± 3% vs. morphine 63 ± 2%, p < 0.05). β-Endorphin also enhanced (p < 0.001) spreading of mesangial cells (at 2 h, control 23 ± 1% vs. β-endorphin 48 ± 3%; at 3 h, control 28 ± 3% vs. β-endorphin 65 ± 1%). Morphine decreased adhesion of mesangial cells to the plastic substrate at 24 h as well at 48 h when compared to the control cells. Naloxone attenuated the effect of morphine on adhesion to the substrate. Morphine enhanced (p < 0.05) migration (percentage of denuded area covered by mesangial cells when compared to control cells (control 26.07 ± 1.08% vs. morphine 37.5 ± 2.94%; n=9). Since the morphine-induced decreased adhesiveness could be attenuated by naloxone, this effect of morphine on mesangial cells appears to be mediated by op