INDUCTION OF APOPTOTIC CELL-DEATH IN A NEUROBLASTOMA CELL-LINE BY DIBUCAINE

Dibucaine, a local anesthetic known to intersect with cell membranes, induced apoptosis in SK-N-MC human neuroblastoma cells in a dose-depen dent manner. Apoptosis was demonstrated by direct visualization of mor phological nuclear changes using a DAPI staining technique and confirm ed by the production of characteristic ladder patterns of DNA fragment ation on gel electrophoresis. At concentrations which induced apoptosi s, dibucaine significantly altered membrane fluidity, indicating that fluidity may be a major target for the cytotoxic action of dibucaine, Also, dibucaine increased intracellular calcium levels more effectivel y in calcium-containing Krebs-Ringer buffer than in calcium-free Krebs -Ringer buffer, Removal of extracellular calcium or addition of antiox idants or protein synthesis inhibitor effectively blocked dibucaine-in duced apoptosis, These results suggest that membrane damage, intracell ular calcium levels, and oxygen free radicals may be involved in the a poptosis induced by dibucaine. (C) 1997 Academic Press.