Open Access5-Hydroxytryptamine Stimulates Phosphorylation of p44/p42 Mitogen-Activated Protein Kinase Activation in Bovine Aortic Endothelial Cell Cultures
Author(s) -
J. Eric McDuffie,
Evangeline D. Motley,
Lee E. Limbird,
M. A. Maleque
Publication year - 2000
Publication title -
journal of cardiovascular pharmacology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.762
H-Index - 100
eISSN - 1533-4023
pISSN - 0160-2446
DOI - 10.1097/00005344-200003000-00008
Subject(s) - mapk/erk pathway , protein kinase a , mitogen activated protein kinase , phosphorylation , enos , microbiology and biotechnology , kinase , endothelial stem cell , chemistry , biology , endocrinology , nitric oxide , biochemistry , nitric oxide synthase , in vitro
5-Hydroxytryptamine (5-HT) is sequestered and released by endothelial cells, acts as an endothelial cell mitogen, promotes the release of nitric oxide (NO), and has been associated with the p44/p42 mitogen-activated protein kinase (MAPK) cascade. NO also acts as a cell mitogen and promotes signals that culminate in the phosphorylation of MAPK. The aim of this study was to test whether endothelial 5-HT receptors stimulate dual (tyrosyl- and threonyl-) phosphorylation of MAPK through a mitogen-activated protein kinase kinase-1 (MEK-1) and eNOS-dependent pathway in bovine aortic endothelial cells (BAECs). As shown by Western blot analysis, 5-HT and the 5-HT1B-selective agonist 5-nonyloxytryptamine (5-NOT) stimulate time- and concentration-dependent (0.001-10 microM) phosphorylation of MAPK in these cells. The agonist-stimulated phosphorylation of MAPK was blocked by the 5-HT1b-receptor antagonist isamoltane (0.01-10 p3M) and the MEK-1 inhibitor PD 098059 ([2-(2'-amino-3'-methoxy-phenyl)-oxanaphthalen-4-one]; 0.01-10 microM¿. The eNOS inhibitor L-N(omega)-iminoethyl-L-ornithine (L-NIO; 0.01-10 microM) failed to block the 1 microM 5-NOT-stimulated responses. Our findings suggest that the 5-HT receptors (specifically 5-HT1B) mediate signals to MEK-1 and subsequently to MAPK through an eNOS-independent pathway in BAECs.