[The cytotoxicity of maitotoxin to LLC-PK(1) and its antagonism to calcium channel blocking agents].
OBJECTIVE
To study the cytotoxicity of maitotoxin (MTX) and its protective effects on calcium-channel blocking agents, so as to provide the data for control and treatment of MTX poisoning.


METHODS
Cytotoxicity was measured by MTT detecting system, and cytoplasmic free [Ca(2+)]i was measured by F-4500 fluorometry.


RESULTS
Incubation with 8 ng/ml MTX for 3 h reduced the survival ratio of LLC-PK(1) cells. The response was found in a time- and concentration-dependent manner, with significant differences as compared with the control group. The MTX-induced increase in [Ca(2+)]i was inhibited by Verapamil and Nifedipine at 5 x 10(-5) mol/L and 1 x 10(-4) mol/L respectively. Both of them significantly reduced the death of the LLC-PK(1) cells.


CONCLUSIONS
Cytotoxicity of MTX may be caused by the elevated intracellular [Ca(2+)]i. Calcium-channel blocking agents could protect LLC-PK(1) cells from injury by MTX.
Liu
Hongying
H
Institute of Pharmacology and Toxicology, Academy of Military Medical Sciences, Beijing 100850, China.
Peng
Shuangqing
S
Shen
Yong
Y
Song
Weizhong
W
D000818:Animals; D002118:Calcium / Q000378:metabolism; D002121:Calcium Channel Blockers / Q000494:pharmacology*; D004336:Drug Antagonism; D018374:LLC-PK1 Cells; D008387:Marine Toxins / Q000633:toxicity*; D009543:Nifedipine / Q000494:pharmacology*; D035964:Oxocins; D013552:Swine; D014700:Verapamil / Q000494:pharmacology*; D000095702:Polyether Toxins
D002118:Calcium; D002121:Calcium Channel Blockers; D008387:Marine Toxins; D009543:Nifedipine; D035964:Oxocins; D014700:Verapamil; C020394:maitotoxin; D000095702:Polyether Toxins