Changes in vasoreactivity of rat pulmonary artery after 7 d tail-suspension.
OBJECTIVE
To clarify the effects of simulated microgravity on the local regulating function of the pulmonary circulation.


METHODS
Rat tail-suspension (TS) was used as the animal model to simulate the effects of microgravity. The changes in responses of pulmonary artery to several vasoactive agents were determined by using in vitro vessel rings perfusion technique.


RESULTS
As for the endothelium-intact vessel rings from TS group compared with those from the control (C) group, the contractile responses of pulmonary artery to potassium chloride (KCl, 10 ~ 70 mmol/L) did not change obviously after 7 d tail-suspension, which were markedly diminished as to phenylephrine (PE, 10(-9) ~ 10(-5) mol/L). The vasodilatory responses to acetylcholine (ACh, 10(-9) ~ 10(-5) mol/L) were markedly enhanced, which did not change obviously as to captopril (Cap, 10(-5) ~ 3 x 10(-3) mol/L). The vasoreactivity of endothelium-removed pulmonary artery rings to all vasoactive agents did not change after 7 d tail-suspension as compared with those from control rats.


CONCLUSIONS
The release of nitric oxide (NO) by rat pulmonary arterial endothelium was enhanced after 7 d tail-suspension. The vasodilatory function of pulmonary artery was enhanced.
Sun
L
L
Institute of Space Medico-Engineering, Beijing.
Wang
D S
DS
Ren
W
W
Xiang
Q L
QL
D000109:Acetylcholine / Q000494:pharmacology; D000818:Animals; D004730:Endothelium, Vascular / Q000187:drug effects / Q000378:metabolism / Q000502:physiology*; D019417:Hindlimb Suspension; D008297:Male; D009569:Nitric Oxide / Q000378:metabolism; D010656:Phenylephrine / Q000494:pharmacology; D011189:Potassium Chloride / Q000494:pharmacology; D011651:Pulmonary Artery / Q000187:drug effects / Q000378:metabolism / Q000502:physiology*; D051381:Rats; D017208:Rats, Wistar; D014661:Vasoconstriction / Q000187:drug effects / Q000502:physiology*; D014662:Vasoconstrictor Agents / Q000494:pharmacology; D014664:Vasodilation / Q000187:drug effects / Q000502:physiology*; D014665:Vasodilator Agents / Q000494:pharmacology; D018474:Weightlessness Simulation
D014662:Vasoconstrictor Agents; D014665:Vasodilator Agents; D010656:Phenylephrine; D009569:Nitric Oxide; D011189:Potassium Chloride; D000109:Acetylcholine