To clarify the neural and humoral factors which control gastric receptive relaxation, the effects of various types of vagotomy or splanchnicotomy on receptive relaxation of the canine innervated corpus pouch were investigated. The influence of gastrin, histamine H1-receptor antagonist, and anti-histamine releasing agents on receptive relaxation were also examined. Selective proximal vagotomy or splanchnicotomy resulted in a slight disturbance in receptive relaxation. Truncal vagotomy produced a marked disturbance in receptive relaxation. Administration of tetragastrin potently inhibited receptive relaxation, however, recovery occurred by injecting a histamine H1-receptor antagonist. Increased serum gastrin induced by perfusion of the antrum with liver extract solution disturbed receptive relaxation and this response was inhibited by pretreatment with transamine, an inhibitor of histamine release from histamine secreting cells. These results indicate that receptive relaxation in the canine stomach is controlled not only by vagal and splanchnic nerves, but also by gastrin and histamine.

Abstract. The effects of physical activity, treadmill running, on bone of ovariectomized mice were investigated. Forty 12-week-old female ICR mice were used. They were ovariectomized (OVX) or shamoperated (SHAM) and half of them were run on a treadmill at 16 m/min, 5 days/week for 6 weeks (Ex). All animals were sacrificed at week 12 after operation. Mechanical strength of the left femur and tibia were measured by the three-point bending strength test. The bones were dried, weighed and burned to ash. Mechanical strength and ash content of the femur and tibia in Ex group were significantly higher than those of control animals. Also mechanical strength of femur and tibia in OVX/Ex were not different from SHAM/Cont mice. Physical activity, treadmill running, thus affected inhibition of bone loss and maintenance of bone mass. It is necessary to continue this basic study to determine effective modes of physical activity.

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The purpose of this study was to clarify the effect of adaptation to and expectation of postural sway caused by perturbation of a platform on initial stances prior to postural response. Twenty healthy university students participated in this study. The joint angles of the ankle, knee, hip, and the neck in initial stance were measured. Adaptation to backward postural sway through repeated perturbations caused the body to tilt backward. However, expectation of backward body sway caused the body to tilt forward, compared with the initial stance when forward body sway was expected. It is suggested that expectation induces the initial stance to stabilize against postural sway mechanically prior to postural response. However, adaptation affects the efficiency of the postural response itself.