BQ-123 INHIBITS BOTH ENDOTHELIN-1 AND ENDOTHELIN-3 MEDIATED C6 RAT GLIOMA CELL-PROLIFERATION SUGGESTING AN ATYPICAL ENDOTHELIN RECEPTOR

The mitogenic action of endothelins (ETs) 1 and 3 was studied on C6 ra t glioma cells in serum-free culture conditions. In order to character ize the ET receptor subtype involved in this effect, BQ-123, an ET(A) receptor selective antagonist was used. Our results confirmed that bot h ET-1 and ET-3 are mitogenic peptides for C6 cells and demonstrated f or the first time that the ET(A) receptor antagonist BQ-123 inhibits t he proliferative effect of both ET-1 and ET-3 in this cellular system, providing evidence of an atypical ET receptor on C6 cells.