Roles of the vestibular system in controlling arterial pressure in conscious rats during a short period of microgravity.
In order to evaluate the roles of the vestibular system in controlling arterial pressure (AP) during exposure to a short period of microgravity (microG), the AP was measured in conscious free-moving rats having intact vestibular systems and those having vestibular lesions (FM-Intact and FM-VL groups, respectively). During free drop-induced microG, the AP increased in the FM-Intact group; it was 38+/-4 mmHg more than the AP observed during 1G. However, the increase in AP was significantly lower in the FM-VL group (20+/-2 mmHg). Further, to examine the sudden effect of a body floating in the midair in response to the AP during exposure to muG a body stabilizer was placed on the back of rats having intact vestibular systems and those having vestibular lesions (STAB-Intact and STAB-VL groups, respectively). The increase in the AP was significantly depressed in the STAB-Intact group; when compared with that in the FM-Intact group, but the increase was still significant (27+/-2 mmHg). On the other hand, the increase in the AP was completely eliminated in the STAB-VL group (7+/-5 mmHg). These results indicate that the AP increases during exposure to muG in conscious rats, and the vestibular system and body stability are significantly involved in this response.
Tanaka
Kunihiko
K
Department of Physiology, Gifu University, Graduate School of Medicine, Gifu 501-1194, Japan. kutanaka@cc.gifu-u.ac.jp
Gotoh
Taro M
TM
Awazu
Chihiro
C
Morita
Hironobu
H
D000818:Animals; D001158:Arteries / Q000502:physiology*; D001794:Blood Pressure / Q000502:physiology*; D003243:Consciousness / Q000502:physiology*; D008297:Male; D051381:Rats; D017207:Rats, Sprague-Dawley; D014722:Vestibule, Labyrinth / Q000293:injuries / Q000502:physiology*; D014893:Weightlessness