B16-BL6 melanoma cells release inhibitory factor(s) of active pump activity in isolated lymph vessels.
We investigated whether supernatant cultured with melanoma cell lines B16-BL6 and K1735 or the Lewis lung carcinoma cell line (LLC) can regulate lymphatic pump activity with bioassay preparations isolated from murine iliac lymph vessels. B16-BL6 and LLC supernatants caused significant dilation of lymph microvessels with cessation of pump activity. B16-BL6 supernatant produced dose-related cessation of lymphatic pump activity. There was no significant tachyphylaxis in the supernatant-mediated inhibitory response of lymphatic pump activity. Pretreatment with 3 x 10(-5) M N(omega)-nitro-L-arginine methyl ester (L-NAME) or 10(-7) M or 10(-6) M glibenclamide and 5 x 10(-4) M 5-hydroxydecanoic acid caused significant reduction of supernatant-mediated inhibitory responses. Simultaneous treatment with 10(-3) M L-arginine and 3 x 10(-5) M L-NAME significantly lessened L-NAME-induced inhibition of the supernatant-mediated response, suggesting that endogenous nitric oxide (NO) plays important roles in supernatant-mediated inhibitory responses. Chemical treatment dialyzed substances of <1,000 molecular weight (MW), producing complete reduction of the supernatant-mediated response. In contrast, pretreatment with heating or digestion with protease had no significant effect on supernatant-mediated response. These findings suggest that B16-BL6 cells may release nonpeptide substance(s) of <1,000 MW, resulting in significant cessation of lymphatic pump activity via production and release of endogenous NO and activation of mitochondrial ATP-sensitive K(+) channels.
Nakaya
K
K
First Department of Physiology, Shinshu University School of Medicine, Shinshu University Graduate School of Medicine, Matsumoto 390-8621, Japan.
Mizuno
R
R
Ohhashi
T
T
D000818:Animals; D000889:Anti-Arrhythmia Agents / Q000494:pharmacology; D001120:Arginine / Q000494:pharmacology; D001681:Biological Assay; D017077:Culture Media, Conditioned; D016861:Cyclooxygenase Inhibitors / Q000494:pharmacology; D003652:Decanoic Acids / Q000494:pharmacology; D010450:Endopeptidases / Q000378:metabolism; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005905:Glyburide / Q000494:pharmacology; D006358:Hot Temperature; D006880:Hydroxy Acids / Q000494:pharmacology; D066298:In Vitro Techniques; D007213:Indomethacin / Q000494:pharmacology; D008196:Lymph / Q000378:metabolism*; D008208:Lymphatic System / Q000378:metabolism*; D008297:Male; D008546:Melanoma, Experimental / Q000378:metabolism*; D051379:Mice; D008815:Mice, Inbred Strains; D019331:NG-Nitroarginine Methyl Ester / Q000494:pharmacology; D010455:Peptides / Q000494:pharmacology; D010477:Perfusion; D014407:Tumor Cells, Cultured
D000889:Anti-Arrhythmia Agents; D017077:Culture Media, Conditioned; D016861:Cyclooxygenase Inhibitors; D003652:Decanoic Acids; D004791:Enzyme Inhibitors; D006880:Hydroxy Acids; D010455:Peptides; C052853:5-hydroxydecanoic acid; C064719:iberiotoxin; D001120:Arginine; D010450:Endopeptidases; D005905:Glyburide; D019331:NG-Nitroarginine Methyl Ester; D007213:Indomethacin