Cytotoxicity of cobra (Naja naja kaouthia) venom on rabbit red blood cells and S-180 tumor cells in the presence of tetracaine, lidocaine and procaine.

The cytocidal action of Naja naja kaouthia venom on rabbit red blood cells and S-180 tumor cells treated with local anesthetics (tetracaine, lidocaine and procaine) were studied. The S-180 cells were more sensitive to the venom than the red blood cells which required albumin for efficient hemolysis in the 10 minute assay. All three local anesthetics at lower concentrations protected both cell types against venom hemolysis. At higher concentrations the local anesthetics enhanced the cell lysis to 100%. The effectiveness of the local anesthetics for both the inhibition and enhancement phases of cytotoxicity was tetracaine greater than lidocaine greater than procaine. This is the same order as their anesthetic effectiveness, lipid solubility and their protein binding.