Central nervous system stimulation in dogs induces a biphasic coronary blood flow response, driven initially by sympathetic vasoconstriction and mechanical compression, and subsequently by metabolic vasodilation.
Highlights central neural influence on coronary vasculature; extends experimental models but leaves open human applicability.
(1) In open-chest, anesthetized dogs with the coronary perfusion pressure kept constant, the brain stem was electrically stimulated and the changes in coronary flow were observed in the course of pressor responses elicited.(2) On stimulation of vasopressor areas, coronary flow showed a biphasic change characterized by an initial slight decrease followed by a subsequent marked increase of longer duration.(3) Changes in heart rate, systole to cycle ratio, and Tension-Time Index were also investigated, and no apparent relationship was shown to exist to coronary flow.(4) The initial transient decrease is partly due to sympathetic coronary vasoconstriction and partly due to increased extravascular compression upon coronary vessels induced by sudden hemodynamic change. The subsequent increase is secondary effect to nervous stimulation.
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UEDA et al. (1964) studied this question.
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