[Effects of simulated weightlessness on vasoreactivity of hindlimb arterial bed in rats].
OBJECTIVE
To investigate the alterations in vasoreactivity of hindlimb arterial bed after simulated weightlessness.


METHODS
The tail-suspended rat model was used to simulate weightlessness, and the alterations in vasoreactivity of arterial bed were examined in vitro using isolated, constant flow perfused hindlimb of 2-wk suspended rats and control rats.


RESULTS
Perfusion flow-pressure relationship of hindlimb arterial bed showed no significant differences between suspended rats and control rats; but vascular responses to KCl (20-100 mM) and PE(10(-8)-10(-4) M) were decreased in hindlimb arterial bed of suspended rats as compared with that of control rats.


CONCLUSIONS
Contractile ability of resistance vessels was diminished in simulated weightlessness rats, and a compromised ability of resistance vessels to increase peripheral resistance may play an important role in occurrence of orthostatic intolerance.
Ma
J
J
Department of Aerospace Physiology, The Fourth Military Medical University, Xi'an, China.
Zhang
L N
LN
Zhang
L F
LF
Yang
T D
TD
D000222:Adaptation, Physiological; D000337:Aerospace Medicine; D000818:Animals; D001158:Arteries / Q000187:drug effects* / Q000502:physiology; D006614:Hindlimb / Q000098:blood supply*; D019417:Hindlimb Suspension; D007024:Hypotension, Orthostatic / Q000209:etiology; D009131:Muscle, Smooth, Vascular / Q000187:drug effects / Q000502:physiology; D010656:Phenylephrine / Q000494:pharmacology; D011189:Potassium Chloride / Q000494:pharmacology; D051381:Rats; D014655:Vascular Resistance / Q000187:drug effects / Q000502:physiology*; D014661:Vasoconstriction / Q000187:drug effects / Q000502:physiology*; D014662:Vasoconstrictor Agents / Q000494:pharmacology; D014666:Vasomotor System / Q000187:drug effects; D018474:Weightlessness Simulation
D014662:Vasoconstrictor Agents; D010656:Phenylephrine; D011189:Potassium Chloride