Fig. 13

Mean responses with superimposed SE of aortic blood flow (AoBF) and total vascular resistance (VR) with arterial pressure at the level of the brain (brain AP) and central venous pressure (CVP) of 11 rats with anti-G equipment exposed to +5.0 Gz acceleration for 15 s. AoBF was measured by a transonic flow probe (2.5 mm diameter, Transonic Systems, Ithaca, NY) which was aseptically implanted on the ascending aorta 2 weeks before the experiments. VR was calculated as [(brain AP-CVP)/AoBF]. The gray area of +Gz shows the moments of anti-G suit functioning. *p < 0.05 and **p < 0.01 by one-factor ANOVA with the Tukey–Kramer test. AoBF decreased significantly greater at the deceleration hypotension than at the acceleration hypotension. VR also decreased significantly greater at the deceleration hypotension than at the acceleration hypotension [17, 18, 22]. The data indicates that one of causes for greater deceleration hypotension is due to lower peripheral resistance produced by release from squeezing pressure of an anti-G suit (based on our experimental data)