Contribution of sustained Ca2+ elevation for nitric oxide production in endothelial cells and subsequent modulation of Ca2+ transient in vascular smooth muscle cells in coculture.
To elucidate the intracellular Ca2+ (Ca2+i ) transient responsible for nitric oxide (NO) production in endothelial cells (ECs) and the subsequent Ca2+i reduction in vascular smooth muscle cells (VSMCs), we administrated four agonists with different Ca2+i-mobilizing mechanisms for both cells in iso- or coculture. We monitored the Ca2+i of both cells by two-dimensional fura-2 imaging, simultaneously measuring NO production as NO2-. The order of potency of the agonists in terms of the peak Ca2+i in ECs was bradykinin (100 nM) > ATP (10 microM) > ionomycin (50 nM) > thapsigargin (1 microM). In contrast, the order in reference to both the extent of Ca2+i reduction in cocultured VSMCs and the elevation in NO production over the level of basal release in ECs completely matched and was ranked as thapsigargin > ionomycin > ATP > bradykinin. Treatment by NG-monomethyl-L-arginine monoacetate but not indomethacin or glybenclamide restored the Ca2+i response in cocultured VSMCs to the isoculture level. In ECs, when the Ca2+ influx was blocked by Ni2+ or by chelating extracellular Ca2+, all four agonists markedly decreased NO production, the half decay time of the Ca2+i degenerating phase, and the area under the Ca2+i curve. The amount of produced NO hyperbolically correlated to the half decay time and the area under the Ca2+i curve but not to the Ca2+i peak level. Thus, the sustained elevation of Ca2+i in ECs, mainly a result of Ca2+ influx, determines the active NO production and subsequent Ca2+i reduction in adjacent VSMCs. Furthermore, L-arginine but not D-arginine or L-lysine at high dose (5 mM) without agonist enhanced the NO production, weakly reduced the Ca2+i in ECs, and markedly decreased the Ca2+i in VSMCs, demonstrating the autocrine and paracrine effects of NO (Shin, W. S., Sasaki, T., Kato, M., Hara, K., Seko, A., Yang, W. D., Shimamoto, N., Sugimoto, T., and Toyo-oka, T. (1992) J. Biol. Chem. 267, 20377-20382).
Wang
Y
Y
Second Department of Internal Medicine, Health Service Center, University of Tokyo, Tokyo 113, Japan.
Shin
W S
WS
Kawaguchi
H
H
Inukai
M
M
Kato
M
M
Sakamoto
A
A
Uehara
Y
Y
Miyamoto
M
M
Shimamoto
N
N
Korenaga
R
R
Ando
J
J
Toyo-oka
T
T
D000818:Animals; D001011:Aorta; D001120:Arginine / Q000031:analogs & derivatives / Q000494:pharmacology; D001920:Bradykinin / Q000494:pharmacology; D002118:Calcium / Q000378:metabolism*; D000252:Calcium-Transporting ATPases / Q000037:antagonists & inhibitors; D002417:Cattle; D002478:Cells, Cultured; D002614:Chelating Agents / Q000494:pharmacology; D018920:Coculture Techniques; D004730:Endothelium, Vascular / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005905:Glyburide / Q000494:pharmacology; D007213:Indomethacin / Q000494:pharmacology; D015759:Ionomycin / Q000494:pharmacology; D007700:Kinetics; D009131:Muscle, Smooth, Vascular / Q000166:cytology / Q000502:physiology*; D009532:Nickel / Q000494:pharmacology; D009569:Nitric Oxide / Q000096:biosynthesis*; D019001:Nitric Oxide Synthase / Q000037:antagonists & inhibitors; D013729:Terpenes / Q000494:pharmacology; D019284:Thapsigargin; D013997:Time Factors; D019323:omega-N-Methylarginine
D002614:Chelating Agents; D004791:Enzyme Inhibitors; D013729:Terpenes; D019323:omega-N-Methylarginine; D009569:Nitric Oxide; D015759:Ionomycin; D019284:Thapsigargin; D009532:Nickel; D001120:Arginine; D019001:Nitric Oxide Synthase; D000252:Calcium-Transporting ATPases; D001920:Bradykinin; D005905:Glyburide; D002118:Calcium; D007213:Indomethacin