[Modulation of iron on the vasodilating effect of interleukin-2 in the isolated aortic ring].
To explore the effect and mechanism of iron on the vasodilating effect of interleukin-2 (IL-2) in the isolated aortic ring.



Isometric tension was recorded in response to drugs in organ bath. Ferric ammonium citrate (FAC) was added to the bath 30 min before phenylephrine (1 micromol/L), which was followed by IL-2 in a cumulative fashion. Spectrophotometry was used to determine the activity of nitric oxide synthase (NOS) of the thoracic aorta.



FAC (0.1 - 10 micromol/L) alone did not affect the tension of rings,but inhibited the vasodilating effect of IL-2 (1 - 1,000 U/ml) in a dose dependent manner. IL-2(1, 10, 100, 1000 U/ml) decreased the aortic tension to (78.47+/-4.31)%, (66.86+/-5.55)%, (52.62+/-4.51)% and (42.39+/-4.27)% of pre-drug control, respectively. However, after incubation with 10 micromol/L FAC in the presence of IL-2, the aortic tension was reduced to (89.81+/-1.94)%, (86.13+/-3.11)%, (77.16+/-5.66)% and (68.76+/-5.69)% of pre-drug control, respectively. Pretreatment with L-arginine (1 mmol/L) abolished the inhibitory effect of FAC. Pretreatment with FAC attenuated the increased activity of NOS induced by IL-2 from (22.10+/-1.87)U/mg prot to (15.71+/-0.89)U/mg prot. High Ca(2+) (2.5 mmol/L) incubation did not change the inhibitory effect of FAC. Pretreatment with FAC attenuated the increased caffeine-releasable pool of Ca(2+) by IL-2. High K(+) (10 mmol/L) incubation abolished the inhibitory effect of FAC.



FAC inhibits the vasodilating effect of IL-2 in the isolated aortic ring,which may be mediated by decreasing the activity of NOS. Intracellular calcium release and inward rectifier potassium channel are involved in the inhibitory effect of FAC.
Wang
Lin-lin
LL
Department of Physiology, College of Medical Sciences, Zhejiang University, Hangzhou 310031, China.
Xia
Qiang
Q
Jin
Hong-feng
HF
Chen
Ying-ying
YY
Shan
Qi-xian
QX
Shen
Ting
T
Sun
Yong
Y
Shen
Yue-liang
YL
D000818:Animals; D001013:Aorta, Thoracic / Q000187:drug effects* / Q000502:physiology; D001120:Arginine / Q000494:pharmacology; D002118:Calcium / Q000378:metabolism; D005290:Ferric Compounds / Q000494:pharmacology*; D066298:In Vitro Techniques; D007376:Interleukin-2 / Q000494:pharmacology*; D008297:Male; D019001:Nitric Oxide Synthase / Q000378:metabolism; D011188:Potassium / Q000494:pharmacology; D000644:Quaternary Ammonium Compounds / Q000494:pharmacology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D014665:Vasodilator Agents / Q000494:pharmacology*
D005290:Ferric Compounds; D007376:Interleukin-2; D000644:Quaternary Ammonium Compounds; D014665:Vasodilator Agents; D001120:Arginine; D019001:Nitric Oxide Synthase; D011188:Potassium; D002118:Calcium; C013531:ferric ammonium citrate