Transmural distribution of blood flow during activation of coronary muscarinic receptors

Gross, G. J.; Buck, J.; Warltier, David C.

doi:10.1152/ajpheart.1981.240.6.h941

Cited by 14 publications

(5 citation statements)

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“…Intracoronary infusion of acetylcholine has been shown to produce redistribution of myocardial blood flow toward the endocardium (Gross et al, 1981). However, although the results of microsphere injection in our experiments showed that endo:epi flow ratios decreased significantly as perfusion pressure was reduced, flow distribution was not further modified by cholinergic reflex vasodilation.…”

Section: Discussioncontrasting

confidence: 75%

Vagal chemoreflex coronary vasodilation evoked by stimulating pulmonary C-fibers in dogs.

Clozel¹,

Roberts²,

Hoffman³

et al. 1985

Circulation Research

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We performed experiments on anesthetized, open-chest dogs to determine whether the pulmonary chemoreflex (bradycardia and systemic hypotension) evoked by stimulating pulmonary C-fibers also involves reflex changes in coronary vascular resistance. We perfused the circumflex coronary artery at constant pressure (usually 100 mm Hg) and recorded mean circumflex blood flow. Stimulation of pulmonary C-fibers by right atrial injection of capsaicin (10 micrograms/kg) decreased arterial blood pressure and heart rate and increased circumflex blood flow by 32-109% (P less than 0.001). Circumflex blood flow also increased, by 26-100% (P less than 0.001), when heart rate was kept constant by pacing. Coronary vasodilation was not secondary to the reflex decrease in arterial blood pressure. Injecting capsaicin (10 micrograms/kg) into the left atrium did not increase circumflex blood flow. Reflex coronary vasodilation could still be evoked when myelinated nerve fibers were blocked selectively by cooling the cervical vagus nerves to 7-8 degrees C but was abolished by cooling to 0 degrees C, by cutting the pulmonary vagal branches, or by giving atropine. Reducing coronary perfusion pressure shifted the stimulus (dose of capsaicin)-response (increase in coronary blood flow) curve to the right, but, even at low perfusion pressures, significant reflex vasodilation still occurred. Regional (transmural) distribution of myocardial blood flow was measured by the microsphere technique at various perfusion pressures. The endocardial:epicardial blood flow ratio decreased significantly as perfusion pressure was reduced, but was not altered by right atrial injection of capsaicin at any perfusion pressure. Our results indicate that stimulation of pulmonary C-fibers triggers reflex cholinergic vasodilation in all layers of the myocardium.

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Section: Discussioncontrasting

confidence: 75%

Vagal chemoreflex coronary vasodilation evoked by stimulating pulmonary C-fibers in dogs.

Clozel¹,

Roberts²,

Hoffman³

et al. 1985

Circulation Research

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“…The cholinergic coronary vasodilatation observed in dogs confirms many previous studies [1][2][3][4][5]. The decrease in coronary blood flow during high doses of acetylcho line in baboons also confirms previous stud ies [8][9][10], but the interpretation is different.…”

Section: Discussionsupporting

confidence: 89%

“…Cholinergic coronary vasodilatation is well recognized in dogs [1], where intracoro nary infusion of acetylcholine [2][3][4][5] ent vagal stimulation [4,6,7] results in an increase in coronary blood flow. In contrast, intracoronary administration of acetylcho line in primates (monkeys and baboons) can produce a decrease in coronary blood flow [8][9][10], A decrease in coronary blood flow due to intracoronary acetylcholine has also been reported in ungulates (cattle) [11,12].…”

Section: Introductionmentioning

confidence: 99%

Cholinergic Vasodilatation of Coronary Resistance Vessels in Dogs, Baboons and Goats

Feigl

Winkle²,

Miyashiro³

1990

J Vasc Res

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Intracoronary infusion of acetylcholine produces a prompt increase in coronary blood flow in dogs, but a paradoxical decrease has been reported in baboons and cattle. The action of acetylcholine was reexamined in anesthetized dogs, baboons and goats, with the coronary circulation pump perfused at constant pressure and the heart rate held constant with electrical pacing. Intracoronary infusions of low doses of acetylcholine produced coronary vasodilatation and an increase in coronary venous oxygen tension without a change in cardiac contractility (dP/dt) or myocardial oxygen consumption in all three species. High doses of acetylcholine produced coronary vasodilatation only in dogs, but resulted in a decrease in cardiac contractility and myocardial oxygen consumption accompanied by a decrease in coronary flow in baboons and goats. It is concluded that low doses of acetylcholine produce coronary vasodilatation in all three species, and that the decrease in coronary blood flow observed in baboons and goats at high doses is probably due to local metabolic vasoconstriction secondary to the negative inotropic effects of acetylcholine.

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“…Studies in swine, calves, and humans with atherosclerosis report vasoconstriction, likely because of the lack of muscarinic receptor expression (198,536,538,1008,1009). Muscarinic coronary vasodilation has been attributed to both M1 and M2 receptors, with stimulation of M2 receptors resulting in the redistribution of blood flow toward the subendocardium (409, 757, 758). …”

Section: Neural Controlmentioning

confidence: 99%

Regulation of Coronary Blood Flow

Goodwill

Dick

Kiel

et al. 2017

Comprehensive Physiology

244

248

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The heart is uniquely responsible for providing its own blood supply through the coronary circulation. Regulation of coronary blood flow is quite complex and, after over 100 years of dedicated research, is understood to be dictated through multiple mechanisms that include extravascular compressive forces (tissue pressure), coronary perfusion pressure, myogenic, local metabolic, endothelial as well as neural and hormonal influences. While each of these determinants can have profound influence over myocardial perfusion, largely through effects on end-effector ion channels, these mechanisms collectively modulate coronary vascular resistance and act to ensure that the myocardial requirements for oxygen and substrates are adequately provided by the coronary circulation. The purpose of this series of Comprehensive Physiology is to highlight current knowledge regarding the physiologic regulation of coronary blood flow, with emphasis on functional anatomy and the interplay between the physical and biological determinants of myocardial oxygen delivery.

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Transmural distribution of blood flow during activation of coronary muscarinic receptors

Cited by 14 publications

References 0 publications

Vagal chemoreflex coronary vasodilation evoked by stimulating pulmonary C-fibers in dogs.

Vagal chemoreflex coronary vasodilation evoked by stimulating pulmonary C-fibers in dogs.

Cholinergic Vasodilatation of Coronary Resistance Vessels in Dogs, Baboons and Goats

Regulation of Coronary Blood Flow

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