Src family tyrosine kinases mediate contraction of rat isolated tail arteries in response to a hyposmotic stimulus.
OBJECTIVE
Hypotonic solutions cause vasoconstriction in rat tail arteries, due largely to activation of L-type calcium channels (CaV1.2). We studied possible roles of tyrosine kinases, particularly src family kinases (SFK) and extracellular signal-related kinases (ERK1/2), in this response.


METHODS
Rat tail arteries were mounted on a myograph for measurement of isometric force. Arteries were bathed in isosmotic physiological saline solution (300 mOsm/l) containing 50 mmol/l mannitol and were stimulated by a hyposmotic solution containing 0 mmol/l mannitol (PSS-M). Activation of tyrosine kinases and ERK1/2 by hyposmotic solution was examined by sodium dodecyl sulphate-polyacrylamide gel electrophoresis and western blotting on rat tail artery lysates with specific phospho-antibodies.


RESULTS
Western blotting showed SFK src and yes present in rat tail artery. PSS-M increased tyrosine phosphorylation of several proteins, including SFK and ERK1/2. Genistein blocked phosphorylation of SFK and ERK1/2 by PSS-M. In isolated arteries PSS-M caused a contraction inhibited by the tyrosine kinase inhibitor, genistein, and three structurally different selective SFK inhibitors, herbimycin-A, PP1 and SU6656. Mitogen-activated protein kinase kinase inhibitor PD98059 or selective inhibitors of platelet-derived growth factor receptor (AG1296) and epidermal growth factor receptor (AG1478) had no effect on contraction induced by a hypotonic solution.


CONCLUSIONS
Hyposmotic conditions activate SFK, src and yes, and contract rat tail artery by a SFK-dependent mechanism. ERK1/2 are activated by the hypotonic solution, but do not play a role in the contractile response. SFK modulation of CaV1.2 may be an important mechanism mediating vasoconstriction to mechanical stimuli in vascular smooth muscle.
Wijetunge
Sumangali
S
Clinical Pharmacology, NHLI Division, Faculty of Medicine, Imperial College London, London, UK. v.wijetunge@imperial.ac.uk
Hughes
Alun D
AD
D000818:Animals; D015153:Blotting, Western; D004591:Electrophoresis, Polyacrylamide Gel; D066298:In Vitro Techniques; D008297:Male; D009994:Osmolar Concentration; D051381:Rats; D017208:Rats, Wistar; D013623:Tail / Q000098:blood supply*; D014661:Vasoconstriction / Q000502:physiology*; D019061:src-Family Kinases / Q000502:physiology*
D019061:src-Family Kinases