OYAMA, JIRO, AND WILLTAM T. PLATT. Reproduction and growth of mice and rats under condz’tions of simulated increased gravity. Am. J* Physiol. ZIQ(I): 164-166. q67.-Mating studies were performed on rats and mice subjected to chronic centrifugation at various g loads. Rats conceived and delivered viable pups at 2.5 and 3.6 g but not at 4.7 g. Newborn pups, however, survived only when they were re...

On Earth, when landing from a counter-movement jump, muscles contract before touchdown to anticipate imminent collision with the ground and place the limbs in a proper position. This study assesses how the control of landing is modified when gravity is increased above 1 g. Hypergravity was simulated in two different ways: (1) by generating centrifugal forces during turns of an aircraft (A300) a...

Several studies have shown that altered gravity causes changes in vestibular induced reflexes and behaviour, and in vestibular morphology. How the level of gravity affects the morphology of vestibular epithelia, however, is largely unknown. Vestibular epithelia of hypergravity (HG) exposed animals and control animals were histochemically labeled for actin and tubulin (two characteristic protein...

Galvanic vestibular stimulation (GVS) is known to create an imbalance in the vestibular inputs; thus it is possible that the simultaneously applied GVS obscures adequate gravity-based inputs to the vestibular organs or modifies an input-output relationship of the vestibular system and then impairs the vestibular-mediated response. To examine this, arterial pressure (AP) response to gravitationa...

We investigated the integrated cardiovascular responses of 15 human subjects to the acute gravitational changes (micro- and hypergravity portions) of parabolic flight. Measurements were made with subjects quietly seated and while subjects performed controlled Valsalva maneuvers. During quiet, seated, parabolic flight, mean arterial pressure increased during the transition into microgravity but ...

Questions about the changes of biological systems in response to hostile environmental factors are important but not easy to answer. Often, the traditional description with differential equations is difficult due to the overwhelming complexity of the living systems. Another way to describe complex systems is by simulating them with phenomenological models such as the well-known evolutionary age...

Adaptation to a novel gravitational state involves adaptation of vestibular mediated responses, in particular those mediated by the otolith organs. The present paper investigates whether the orientation of Listing's plane, which is under control of otolith signals, is affected by sustained exposure to hypergravity. Subjects were exposed to four G-loads differing in duration (45 or 90 min) and m...