title: Effects of microgravity elicited by parabolic flight on abdominal aortic pressure and heart rate in rats.
abstract: 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.
authors.affiliation: Department of Physiology, Fukushima Medical University School of Medicine, Fukushima 960-1295, Japan. wakihidefumi@aol.com
authors.forename: Hidefumi
authors.initials: H
authors.lastname: Waki
authors.forename: Tsuyoshi
authors.initials: T
authors.lastname: Shimizu
authors.forename: Kiyoaki
authors.initials: K
authors.lastname: Katahira
authors.forename: Tadanori
authors.initials: T
authors.lastname: Nagayama
authors.forename: Masao
authors.initials: M
authors.lastname: Yamasaki
authors.forename: Shin-Ichiro
authors.initials: S
authors.lastname: Katsuda
mesh_terms: 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
chemical_list: D018686:Anesthetics, Intravenous; D014520:Urethane