Calcium-mediated endothelin signaling in C6 rat glioma cells.
Endothelin induced intracellular Ca(2+)signaling was studied in C6 rat glial cells. Endothelins 1 and 3 increased transiently intracellular Ca(2+)concentration, endothelin 3 being less potent inducer. Dibutyryl-cAMP treated cells responded with less sensitivity. While BQ123, a specific endothelin A receptor antagonist, inhibited both endothelins induced response in proliferating cells, it failed to inhibit in dibutyryl-cAMP treated ones. IRL1620, a specific endothelin B receptor agonist, was devoid of any significant effect. Although re-stimulation by both endothelins after endothelin-1 did not cause any Ca(2+)oscillation, both endothelins evoked new Ca(2+)transient after endothelin-3 stimulation. Our findings suggest that endothelin induced Ca(2+)signaling is mediated probably through the receptor A in proliferating C6 cells. The lack of both BQ123 and IRL 1620 effect in dibutyryl-cAMP treated cells could be caused by an alteration of endothelin A receptor alone, by a change of receptor expression pattern, or by more complex postreceptor mechanism.
Sedo
A
A
1st Institute of Medical Chemistry and Biochemistry, 1st Faculty of Medicine, Charles University, Prague, Czech Republic. Aleksi@MBOX.CESNET.CZ
Malík
R
R
Vlăsicová
K
K
Rovero
P
P
D000818:Animals; D003994:Bucladesine / Q000494:pharmacology; D002118:Calcium / Q000378:metabolism; D020013:Calcium Signaling / Q000187:drug effects* / Q000502:physiology*; D002454:Cell Differentiation / Q000502:physiology; D019332:Endothelin-1 / Q000494:pharmacology*; D019334:Endothelin-3 / Q000494:pharmacology*; D005910:Glioma; D051381:Rats; D017466:Receptors, Endothelin / Q000502:physiology; D014407:Tumor Cells, Cultured / Q000737:chemistry / Q000166:cytology / Q000502:physiology
D019332:Endothelin-1; D019334:Endothelin-3; D017466:Receptors, Endothelin; D003994:Bucladesine; D002118:Calcium