The effects of maitotoxin on phosphoinositides and calcium metabolism in a primary culture of aortic smooth muscle cells.
Toxicon
; 26(2): 133-41, 1988.
Article
in En
| MEDLINE
| ID: mdl-2834835
ABSTRACT
Maitotoxin, a potent marine toxin isolated from toxic tropical dinoflagellates and poisonous fishes induces contraction of different smooth muscle preparations. Actions of maitotoxin on phosphoinositides and calcium metabolism were studied using a primary culture of aortic smooth muscle cells. Maitotoxin induced a very large increase of cytosolic calcium concentration as evaluated by fura-2 acetoxymethyl ester fluorescence. This increase was concomitant with stimulation of inositol-phosphate accumulation and loss of viability of aortic smooth muscle cells. These responses to maitotoxin were abolished in Ca2+-free medium, and were mimicked by saponin. Calcium ionophores or K+ depolarisation did not induce inositol-phosphate formation. These results suggest that maitotoxin acts by altering smooth muscle cells permeability allowing a sustained calcium influx which is able to activate inositol-phosphate formation and which is lethal for the cells.
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Collection:
01-internacional
Database:
MEDLINE
Main subject:
Phosphatidylinositols
/
Calcium
/
Fura-2
/
Oxocins
/
Marine Toxins
/
Muscle, Smooth, Vascular
Limits:
Animals
Language:
En
Journal:
Toxicon
Year:
1988
Document type:
Article
Affiliation country:
France