15-hydroxy-11-alpha-9-alpha-(epoxymethano)prosta-5-13-dienoic-acid and herbimycin

We investigated the effects of vascular endothelial growth factor (VEGF(165)) on [Ca(2+)](i)-transient in cultured lymphatic endothelial cells (LEC) and mechanical activity of isolated dog thoracic ducts. VEGF (0.1-10 ng/ml) caused a dose-dependent increase of the [Ca(2+)](i) in LEC. Pretreatment with 10(-5) M genistein or 5x10(-6) M herbimycin A produced a significant reduction of the VEGF-induced [Ca(2+)](i)-transient. In the presence of 10(-6) M thapsigargin, VEGF caused no significant effect on the [Ca(2+)](i)-transient. Pretreatment with Ca(2+)-free solution containing 0.1 mM EGTA produced no significant effect on the peak increase of [Ca(2+)](i) induced by 0.1 or 10 ng/ml VEGF, but significantly depressed the sustained part of [Ca(2+)](i) observed at the higher concentration of VEGF. The VEGF (0.1-10 ng/ml) caused a significant dilation of the isolated lymph vessels with intact endothelium, which were precontracted with U46,619. The 10 ng/ml VEGF-induced dilation was significantly reduced by 3 x 10(-5) M N(omega)-nitro-L-arginine methyl ester (L-NAME). The action of L-NAME was inhibited by the simultaneous application of 10(-3) M L-arginine. Mechanical rubbing of the endothelium also caused significant inhibition of the VEGF-induced dilation. The findings suggest that VEGF(165) may activate the receptor-related tyrosine kinase and cause the release of Ca(2+) from the inositol 1,4, 5-triphosphate-sensitive intracellular Ca(2+) stores in LEC. VEGF(165) also produces endothelium-dependent nitric oxide-mediated dilation of the precontracted isolated lymph vessels.

Topics: 15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5,13-dienoic Acid; Animals; Antibiotics, Antineoplastic; Arginine; Benzoquinones; Biological Transport; Calcium; Cells, Cultured; Chelating Agents; Dogs; Egtazic Acid; Endothelial Growth Factors; Endothelium, Lymphatic; Enzyme Inhibitors; Female; Genistein; Growth Inhibitors; In Vitro Techniques; Lactams, Macrocyclic; Lymph; Lymphokines; Male; NG-Nitroarginine Methyl Ester; Nitric Oxide; Nitroprusside; Potassium; Quinones; Rifabutin; Stress, Mechanical; Thapsigargin; Thoracic Duct; Vascular Endothelial Growth Factor A; Vascular Endothelial Growth Factors; Vasoconstrictor Agents; Vasodilator Agents

In order to determine whether protein tyrosine kinase mechanisms are involved in pressure-induced contraction, we compared effects of three structurally unrelated tyrosine kinase inhibitors and orthovanadate, a tyrosine phosphatase inhibitor, on the pressure-induced contraction of the posterior cerebral artery isolated from rats. The change in vessel diameter was continuously measured with a width analyzer. Herbimycin A inhibited the pressure-induced contraction, while it only slightly inhibited contractions produced by potassium chloride or 9,11-dideoxy-11alpha,9alpha-epoxymethano prostaglandin F2alpha (U46619). Genistein inhibited not only the pressure-induced contraction but also the U46619-induced one. Tyrphostin 23 significantly attenuated contractions in response to three different stimuli, i.e., pressure, potassium chloride and U46619. Orthovanadate potentiated the pressure-induced contraction. These results suggest that herbimycin A is a specific and potent inhibitor of the pressure-induced contraction and that a protein tyrosine kinase mechanism may play an important role in the genesis of the pressure-induced contraction of the rat cerebral artery.

Topics: 15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5,13-dienoic Acid; Animals; Benzoquinones; Catechols; Cerebral Arteries; Genistein; In Vitro Techniques; Isoflavones; Lactams, Macrocyclic; Male; Muscle Contraction; Muscle, Smooth, Vascular; Nitriles; Potassium Chloride; Pressure; Prostaglandin Endoperoxides, Synthetic; Protein-Tyrosine Kinases; Quinones; Rats; Rats, Sprague-Dawley; Rifabutin; Thromboxane A2; Tyrphostins; Vanadates; Vasoconstrictor Agents