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c‐Src tyrosine kinase, a critical component for 5‐HT 2A receptor‐mediated contraction in rat aorta
Author(s) -
Lu Rong,
Alioua Abderrahmane,
Kumar Yogesh,
Kundu Pallob,
Eghbali Mansoureh,
Weisstaub Noelia V.,
Gingrich Jay A.,
Stefani Enrico,
Toro Ligia
Publication year - 2008
Publication title -
the journal of physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.802
H-Index - 240
eISSN - 1469-7793
pISSN - 0022-3751
DOI - 10.1113/jphysiol.2008.153593
Subject(s) - proto oncogene tyrosine protein kinase src , contraction (grammar) , tyrosine kinase , chemistry , aorta , microbiology and biotechnology , receptor , receptor tyrosine kinase , biophysics , endocrinology , medicine , biology , biochemistry
Serotonin (5‐hydroxytryptamine, 5‐HT) receptors (5‐HTRs) play critical roles in brain and cardiovascular functions. In the vasculature, 5‐HT induces potent vasoconstrictions, which in aorta are mainly mediated by activation of the 5‐HT 2A R subtype. We previously proposed that one signalling mechanism of 5‐HT‐induced vasoconstriction could be c‐Src, a member of the Src tyrosine kinase family. We now provide evidence for a central role of c‐Src in 5‐HT 2A R‐mediated contraction. Inhibition of Src kinase activity with 10 μ m 4‐amino‐5‐(4‐chlorophenyl)‐7‐( t ‐butyl)pyrazolo[3,4‐d]pyrimidine (PP2) prior to contraction resulted in ∼90–99% inhibition of contractions induced by 5‐HT or by α‐methyl‐5‐HT (5‐HT 2 R agonist). In contrast, PP2 pretreatment only partly inhibited contractions induced by angiotensin II and the thromboxane A 2 mimetic, U46619, and had no significant action on phenylephrine‐induced contractions. 5‐Hydroxytryptamine increased Src kinase activity and PP2‐sensitive tyrosine‐phosphorylated proteins. As expected for c‐Src identity, PP2 pretreatment inhibited 5‐HT‐induced contraction with an IC 50 of ∼1 μ m . Ketanserin (10 n m ), a 5‐HT 2A antagonist, but not antagonists of 5‐HT 2B R (100 n m SB204741) or 5‐HT 2C R (20 n m RS102221), prevented 5‐HT‐induced contractions, mimicking PP2 and implicating 5‐HT 2A R as the major receptor subtype coupled to c‐Src. In HEK 293T cells, c‐Src and 5‐HT 2A R were reciprocally co‐immunoprecipitated and co‐localized at the cell periphery. Finally, 5‐HT‐induced Src activity was unaffected by inhibition of Rho kinase, supporting a role of c‐Src upstream of Rho kinase. Together, the results highlight c‐Src activation as one of the early and pivotal mechanisms in 5‐HT 2A R contractile signalling in aorta.