Calcium calmodulin in altered NaCl transport by heat-labile enterotoxin of Escherichia coli.
The mucosal-to-serosal and serosal-to-mucosal fluxes of Na+ and Cl- were carried out in control and experimental groups treated with different doses of heat-labile enterotoxin in the presence or absence of Ca2+-ionophore, Ca2+ channel blocker and calmodulin inhibitor. There was net secretion of Na+ and Cl- in 16 and 32 units of heat-labile enterotoxin treated groups in comparison to net absorption in control group, however, in animals treated with 8 units of heat-labile enterotoxin, no change in Na+ and Cl- fluxes was found when compared to control. Ca2+- ionophore increased net secretion of Na+ and Cl- in 16 and 32 units of heat-labile enterotoxin treated groups and also caused secretion in control group instead of net absorption. Ca2+ channel blocker and calmodulin inhibitor partially reversed the effect of heat-labile enterotoxin. The effect of Ca2+-ionophore was more pronounced in the control group while that of Ca2+ channel blocker and calmodulin inhibitor was more pronounced in 16 and 32 units of heat-labile enterotoxin treated groups. The findings suggest the involvement of Ca2+ and calmodulin in the action of heat-labile enterotoxin of Escherichia coli in mice.
Goyal
J
J
Department of Paediatrics, Postgraduate Institute of Medical Education and Research, Chandigarh, India.
Ganguly
N K
NK
Garg
U C
UC
Walia
B N
BN
D000818:Animals; D001427:Bacterial Toxins / Q000494:pharmacology*; D001693:Biological Transport, Active; D000001:Calcimycin / Q000494:pharmacology; D002147:Calmodulin / Q000037:antagonists & inhibitors / Q000378:metabolism*; D002712:Chlorides / Q000378:metabolism*; D004768:Enterotoxins / Q000494:pharmacology*; D004926:Escherichia coli; D029968:Escherichia coli Proteins; D051379:Mice; D011817:Rabbits; D012964:Sodium / Q000378:metabolism*; D014268:Trifluoperazine / Q000494:pharmacology; D014700:Verapamil / Q000494:pharmacology
D001427:Bacterial Toxins; D002147:Calmodulin; D002712:Chlorides; D004768:Enterotoxins; D029968:Escherichia coli Proteins; D014268:Trifluoperazine; D000001:Calcimycin; D012964:Sodium; D014700:Verapamil; C027538:heat-labile enterotoxin, E coli