Effects of microgravity elicited by parabolic flight on abdominal aortic pressure and heart rate in rats.
Abdominal aortic pressure (AAP), heart rate (HR), and aortic nerve activity (ANA) during parabolic flight were measured by using a telemetry system to clarify the acute effect of microgravity (microG) on hemodynamics in rats. While the animals were conscious, AAP increased up to 119 +/- 3 mmHg on exposure to microG compared with the value at 1 G (95 +/- 3 mmHg; P < 0.001), whereas AAP decreased immediately on exposure to microG under urethane anesthesia (microG: 72 +/- 9 mmHg vs. 1 G: 78 +/- 8 mmHg; P < 0.05). HR also increased during microG in conscious animals (microG: 349 +/- 12 beats/min vs. 1 G: 324+9 beats/min; P < 0.01), although no change was observed under anesthesia. ANA, which was measured under anesthesia, decreased in response to acute microG exposure (microG: 33 +/- 7 counts/s vs. 1 G: 49 +/- 5 counts/s; P < 0.01). These results suggest that microG essentially induces a decrease of arterial pressure; however, emotional stress and body movements affect the responses of arterial pressure and HR during exposure to acute microG.
Waki
Hidefumi
H
Department of Physiology, Fukushima Medical University School of Medicine, Fukushima 960-1295, Japan. wakihidefumi@aol.com
Shimizu
Tsuyoshi
T
Katahira
Kiyoaki
K
Nagayama
Tadanori
T
Yamasaki
Masao
M
Katsuda
Shin-Ichiro
S
D000401:Aircraft; D018686:Anesthetics, Intravenous / Q000494:pharmacology; D000818:Animals; D001012:Aorta, Abdominal / Q000294:innervation / Q000502:physiology*; D001794:Blood Pressure / Q000187:drug effects / Q000502:physiology*; D003243:Consciousness; D003714:Denervation; D006339:Heart Rate / Q000187:drug effects / Q000502:physiology*; D008297:Male; D051381:Rats; D017207:Rats, Sprague-Dawley; D013686:Telemetry; D014520:Urethane / Q000494:pharmacology; D018474:Weightlessness Simulation
D018686:Anesthetics, Intravenous; D014520:Urethane