8 Post-exercise Hypotension in Hypertensive Subjects: Cardiovascular Responses to Lower Body Negative Pressure

1983 ◽  
Vol 1 (3) ◽  
pp. 314
Author(s):  
T Bennett ◽  
R G Wilcox ◽  
I A Macdonald
Keyword(s):  
Negative Pressure ◽  
Lower Body Negative Pressure ◽  
Cardiovascular Responses ◽  
Lower Body ◽  
Post Exercise ◽  
Post Exercise Hypotension

RECOVERY OF CARDIOVASCULAR RESPONSES TO LOWER BODY NEGATIVE PRESSURE (LBNP) AFTER SPACE FLIGHT 203

1997 ◽  
Vol 29 (Supplement) ◽  
pp. 36
Author(s):  
S. M.C. Lee ◽  
L. Steinmann ◽  
M. Wood ◽  
L. Dussack ◽  
S. M. Fortney
Keyword(s):  
Space Flight ◽  
Negative Pressure ◽  
Lower Body Negative Pressure ◽  
Cardiovascular Responses ◽  
Lower Body

Effect of hindlimb suspension on cardiovascular responses to sympathomimetics and lower body negative pressure

1990 ◽  
Vol 68 (1) ◽  
pp. 355-362 ◽  
Author(s):  
J. M. Overton ◽  
C. M. Tipton
Keyword(s):  
Negative Pressure ◽  
Lower Body Negative Pressure ◽  
Cardiovascular Responses ◽  
Male Rats ◽  
Hindlimb Suspension ◽  
Lower Body ◽  
Baroreflex Control ◽  
Cardiovascular Deconditioning ◽  
Treatment Conditions ◽  
Before And After

To determine whether hindlimb suspension is associated with the development of cardiovascular deconditioning, male rats were studied before and after undergoing one of three treatment conditions for 9 days: 1) cage control (n = 15, CON), 2) horizontal suspension (n = 15, HOZ), and 3) head-down suspension (n = 18, HDS). Testing included lower body negative pressure administered during chloralose-urethan anesthesia and graded doses of sympathomimetic agents (norepinephrine, phenylephrine, and tyramine) administered to conscious unrestrained animals. Both HDS and HOZ were associated with a small decrease in the hypotensive response to lower body negative pressure. The HOZ group, but not the HDS group, exhibited augmented reflex tachycardia. Furthermore, both HDS and HOZ groups manifested reduced pressor responses to phenylephrine after treatment. These reductions were associated with significantly attenuated increases in mesenteric vascular resistance. However, baroreflex control of heart rate was not altered by the treatment conditions. Collectively, these results indicate that 9 days of HDS in rats does not elicit hemodynamic response patterns generally associated with cardiovascular deconditioning induced by hypogravic conditions.

Hysteresis in response to descending and ascending lower-body negative pressure

1987 ◽  
Vol 63 (2) ◽  
pp. 719-725 ◽  
Author(s):  
C. M. Tomaselli ◽  
M. A. Frey ◽  
R. A. Kenney ◽  
G. W. Hoffler
Keyword(s):  
Negative Pressure ◽  
Lower Body Negative Pressure ◽  
Cardiovascular Responses ◽  
Orthostatic Stress ◽  
Lower Body ◽  
Test Protocol ◽  
Fluid Movement ◽  
Venous Pooling ◽  
Fluid Redistribution ◽  
Reversible Component

We have investigated the pattern of fluid redistribution and cardiovascular responses during graduated orthostatic stress. Twelve men, age 30–39 yr, underwent a 25-min lower-body negative pressure (LBNP) test protocol that involved sequential stages of LBNP at -8 mmHg (1 min), -16 mmHg (1 min), -30 mmHg (3 min), -40 mmHg (5 min), -50 mmHg (5 min), -40 mmHg (5 min), -30 mmHg (3 min), -16 mmHg (1 min), and -8 mmHg (1 min). Data were recorded at the end of each stage. For many measured variables values during the descending phase of LBNP (-8 to -40 mmHg) were significantly different from values during the ascending phase of (-40 to -8 mmHg). These differences appear to be due to a component of fluid translocation that occurs during LBNP and cannot be reversed within the duration of the procedure. We hypothesize that this slowly reversed component is sequestration of fluid in the interstitial and lymphatic compartments. In contrast, venous pooling is a rapidly reversible component of fluid movement during LBNP. A scheme describing fluid and cardiovascular responses to LBNP based on these data and the data of other investigators is presented.

Rodent cardiovascular responses to baroreceptor unloading: Effect of plane of anaesthesia

2011 ◽  
Vol 36 (3) ◽  
pp. 376-381 ◽  
Author(s):  
Charlotte W. Usselman ◽  
Louis Mattar ◽  
Jasna Twynstra ◽  
Ian Welch ◽  
J. Kevin Shoemaker
Keyword(s):  
Heart Rate ◽  
Mean Arterial Pressure ◽  
Arterial Pressure ◽  
Vascular Resistance ◽  
Negative Pressure ◽  
Lower Body Negative Pressure ◽  
Cardiovascular Responses ◽  
Cardiovascular Control ◽  
Noxious Stimulation ◽  
Lower Body

The objective of this study was to determine whether a plane of urethane–α-chloralose anaesthesia that suppresses motor reflexes would affect baroreflex cardiovascular control relative to a plane of anaesthesia that leaves motor reflexes intact. Adult male Sprague–Dawley rats were anaesthetized to either a light (motor reflexes intact) or deep (motor reflexes suppressed) plane of anaesthesia. Animals were exposed to graded (–2 to –10 mm Hg) lower body negative pressure while heart rate, vascular resistance, and mean arterial pressure were assessed. No between-group differences were observed in baseline hemodynamics. Graded lower body negative pressure progressively increased heart rate (p < 0.01) and vascular resistance (p < 0.001) and reduced mean arterial pressure (p < 0.001) similarly in light and deep planes of anaesthesia. Therefore, the deep plane of anaesthesia was not associated with a degradation of the autonomic response to baroreceptor unloading beyond that observed at the light plane. These data support the use of urethane–α-chloralose anaesthesia in studies examining reflex cardiovascular control concomitant with some degree of noxious stimulation.

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