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The role of pressoreceptors in the regulation of blood pressure in the rabbit
Abstracts
and Reviews
Selected WBgria, Shock
R., Rojas, A. G., and in a Heart-Lung-Dog
Abstracts
A Study of Spontaneous Wiggers, C. J.: Preparation. Am. J. Physiol. 138: 212,
Pulminant 1943.
The relative importance of (a) decrease in venous pressure and secondary reduction of cardiac output, (b) primary myocsrdial impairment, and (c) changes in total peripheral resistance (TPR) in shock was studied by means of a heart-lung-dog Venous flow and cardiac output were under eonpreparation, which is described. In such a preparation, a fulminant type of shock trol, and TPR could be calculated. develops spontaneously which may resemble clinical types characterized by speedy circulatory failure and death. In twenty-four such experiments it was shown (a) that shock can develop without progressive reduction or even with a rise of venous pressures or cardiac output, and (b) that it cannot be prevented or cured by inereased venous inflow and cardiac output. The fundamental factor responsible for this type of irreversible cireu1ator.v failure was a steady and pronounced decrease in total peripheral resistance, which enabled the animal to store, over and above its own blood volume, quantities of blood equal to 25 per cent of its body weight, or four times its omn blood volume. Autopsies revealed no storage depots other than the mucosa of the upper intestines, which was always edematous, intensely congested, and often hemorrhagic. The integration of these observations with apparently contrary findings regarding the state of the peripheral circulation, and their application to fulminant types of shock in man are discussed. Following any prolonged period of hypotension during the development of shock, the cardiac output at equivalent venous pressures also decreased, indicating that depression of the myocardium occurred. In the form of shock studied, this did not prove to be an initiating factor nor was it necessary to produce an irreversible state. But, after the peripheral changes of shock had been well established, it played an important role in the .rapid downward trend of blood pressure and was the ultimate cause of death. Five dogs, primed with liberal doses of cortical adrenal extracts, and receiving these extracts during the experiments, revealed no indications that the course of dynamic events or the pathologic changes in the intestinal mucosa were influenced. It must be recognized, however, that the authors’ preparatiocs perhaps offered too severe a test. AUTHORS.
Simister, T. H., and of Blood Pressure
Conklin, in the
R. 33.: Rabbit.
The Role of Pressoreceptors Sm. J. Physiol. 138: 391,
in the Regulation 1943.
Brief tipping experiments have been done on thirty-two rabbits, with progressive elimination of sources of afferent impulses causing reflex circulatory compensation. It has been shown that the rabbit is still able to compensate to some extent for the effect of gravity when it is deprived of vagi, aortic nerves, carotid sinuses and splanchnic nerves. Some other reflexogenic sources, responsible for the compensation, must exist. AUTNORS. 275
and Reviews
Selected WBgria, Shock
R., Rojas, A. G., and in a Heart-Lung-Dog
Abstracts
A Study of Spontaneous Wiggers, C. J.: Preparation. Am. J. Physiol. 138: 212,
Pulminant 1943.
The relative importance of (a) decrease in venous pressure and secondary reduction of cardiac output, (b) primary myocsrdial impairment, and (c) changes in total peripheral resistance (TPR) in shock was studied by means of a heart-lung-dog Venous flow and cardiac output were under eonpreparation, which is described. In such a preparation, a fulminant type of shock trol, and TPR could be calculated. develops spontaneously which may resemble clinical types characterized by speedy circulatory failure and death. In twenty-four such experiments it was shown (a) that shock can develop without progressive reduction or even with a rise of venous pressures or cardiac output, and (b) that it cannot be prevented or cured by inereased venous inflow and cardiac output. The fundamental factor responsible for this type of irreversible cireu1ator.v failure was a steady and pronounced decrease in total peripheral resistance, which enabled the animal to store, over and above its own blood volume, quantities of blood equal to 25 per cent of its body weight, or four times its omn blood volume. Autopsies revealed no storage depots other than the mucosa of the upper intestines, which was always edematous, intensely congested, and often hemorrhagic. The integration of these observations with apparently contrary findings regarding the state of the peripheral circulation, and their application to fulminant types of shock in man are discussed. Following any prolonged period of hypotension during the development of shock, the cardiac output at equivalent venous pressures also decreased, indicating that depression of the myocardium occurred. In the form of shock studied, this did not prove to be an initiating factor nor was it necessary to produce an irreversible state. But, after the peripheral changes of shock had been well established, it played an important role in the .rapid downward trend of blood pressure and was the ultimate cause of death. Five dogs, primed with liberal doses of cortical adrenal extracts, and receiving these extracts during the experiments, revealed no indications that the course of dynamic events or the pathologic changes in the intestinal mucosa were influenced. It must be recognized, however, that the authors’ preparatiocs perhaps offered too severe a test. AUTHORS.
Simister, T. H., and of Blood Pressure
Conklin, in the
R. 33.: Rabbit.
The Role of Pressoreceptors Sm. J. Physiol. 138: 391,
in the Regulation 1943.
Brief tipping experiments have been done on thirty-two rabbits, with progressive elimination of sources of afferent impulses causing reflex circulatory compensation. It has been shown that the rabbit is still able to compensate to some extent for the effect of gravity when it is deprived of vagi, aortic nerves, carotid sinuses and splanchnic nerves. Some other reflexogenic sources, responsible for the compensation, must exist. AUTNORS. 275