Src family kinase involvement in rat preglomerular microvascular contractile and [Ca2+]i responses to ANG II.
Experiments were performed to investigate the potential role of Src family kinase(s) in the rat afferent arteriolar contractile response to ANG II. The in vitro blood-perfused juxtamedullary nephron technique was employed to monitor afferent arteriolar lumen diameter responses to 1-100 nM ANG II before and during Src family kinase inhibition (10 microM PP2). PP2 did not alter baseline diameter but attenuated ANG II-induced contractile responses by 33 +/- 6%. An inactive analog of PP2 (PP3) had no effect on ANG II-induced afferent arteriolar contraction. The effect of Src kinase inhibition on ANG II-induced intracellular free Ca(2+) concentration ([Ca(2+)](i)) responses was probed in fura 2-loaded preglomerular microvascular smooth muscle cells (PVSMCs) obtained from explants and studied after 3-5 days in culture. In untreated PVSMCs, ANG II evoked peak (Delta = 293 +/- 66 nM) and plateau (Delta = 23 +/- 8 nM) increases in [Ca(2+)](i). In PVSMCs pretreated with PP2, baseline [Ca(2+)](i) was unaltered, but both the peak (Delta = 140 +/- 22 nM) and plateau (Delta = 3 +/- 2 nM) phases of the ANG II response were significantly reduced compared with untreated cells. PP3 did not alter [Ca(2+)](i) responses to ANG II. Immunoprecipitation and Western blot analysis confirmed that 100 nM ANG II increased phosphorylation of c-Src (at Y(416)) in PVSMCs. The phosphorylation response was maximal 1 min after ANG II exposure and was prevented by PP2. We conclude that the preglomerular vasoconstriction evoked by ANG II involves rapid c-Src activation with subsequent effects that contribute to the [Ca(2+)](i) response to the peptide.
Che
Qi
Q
Dept. of Cellular and Integrative Physiology, Univ. of Nebraska College of Medicine, 985850 Nebraska Medical Ctr., Omaha, NE 68198-5850, USA.
Carmines
Pamela K
PK
D000804:Angiotensin II / Q000494:pharmacology*; D000818:Animals; D001160:Arterioles / Q000166:cytology / Q000187:drug effects / Q000201:enzymology; D002118:Calcium / Q000378:metabolism*; D002478:Cells, Cultured; D007606:Juxtaglomerular Apparatus / Q000098:blood supply* / Q000201:enzymology; D007678:Kidney Glomerulus / Q000098:blood supply* / Q000201:enzymology; D008297:Male; D009131:Muscle, Smooth, Vascular / Q000166:cytology / Q000187:drug effects / Q000201:enzymology; D010766:Phosphorylation / Q000187:drug effects; D051381:Rats; D017207:Rats, Sprague-Dawley; D014661:Vasoconstriction / Q000187:drug effects / Q000502:physiology; D014662:Vasoconstrictor Agents / Q000494:pharmacology*; D019061:src-Family Kinases / Q000378:metabolism*
D014662:Vasoconstrictor Agents; D000804:Angiotensin II; D019061:src-Family Kinases; D002118:Calcium