Sensitivity of rabbit aorta and mesenteric artery to norepinephrine: role of tyrosine kinases.
We tested the hypothesis that the differential sensitivity of rabbit aorta and mesenteric artery to norepinephrine is due to tyrosine kinase activity. The EC50 of aorta to norepinephrine was 6.5 times more sensitive than that in mesenteric artery. Basal myosin light chain phosphorylation was significantly greater in aorta as compared to mesenteric artery. Vanadate increased norepinephrine sensitivity significantly more in mesenteric artery than aorta, whereas genistein had the opposite effect. Basal phosphotyrosine levels were significantly higher in aorta than in mesenteric artery, the percentage increase in total tyrosine phosphorylated protein was significantly higher in mesenteric artery. These results suggest that the higher basal phosphotyrosine levels in the aorta may be responsible for the higher basal level of myosin light chain phosphorylation and this may be the basis for the higher sensitivity of the aorta to norepinephrine when compared with the mesenteric artery.
Adegunloye
Banji J
BJ
Department of Pharmacology and Physiology, Drexel University College of Medicine, 245 N 15th Street, MS# 488, Philadelphia, PA 19102, USA.
Su
Xiaoling
X
Camper
Elaan V
EV
Moreland
Robert S
RS
D000818:Animals; D001013:Aorta, Thoracic / Q000187:drug effects / Q000378:metabolism* / Q000502:physiology; D015153:Blotting, Western; D004591:Electrophoresis, Polyacrylamide Gel; D019833:Genistein / Q000494:pharmacology; D066298:In Vitro Techniques; D007537:Isometric Contraction / Q000187:drug effects; D008297:Male; D008638:Mesenteric Arteries / Q000187:drug effects / Q000378:metabolism* / Q000502:physiology; D009131:Muscle, Smooth, Vascular / Q000187:drug effects / Q000378:metabolism / Q000502:physiology; D018994:Myosin Light Chains / Q000378:metabolism; D009638:Norepinephrine / Q000494:pharmacology*; D010766:Phosphorylation; D019000:Phosphotyrosine / Q000378:metabolism; D011505:Protein-Tyrosine Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism*; D011817:Rabbits; D011941:Receptors, Adrenergic / Q000378:metabolism; D013997:Time Factors; D014662:Vasoconstrictor Agents / Q000494:pharmacology*
D018994:Myosin Light Chains; D011941:Receptors, Adrenergic; D014662:Vasoconstrictor Agents; D019000:Phosphotyrosine; D019833:Genistein; D011505:Protein-Tyrosine Kinases; D009638:Norepinephrine