Chemoreception und lokale Adrenalinwirkung am sinus caroticus

Kalkoff, W; Plischke, K. H.; Rath, Friedrich-Wilhelm

doi:10.1007/bf00380411

Cited by 9 publications

(2 citation statements)

References 14 publications

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“…However, as aortic diameter (measured in the undisturbed receptor area) was decreased during the infusion, the present results imply that the excitability of the aortic stretch receptors was increased by norepinephrine. We know from earlier work that external application of vasoconstrictor drugs to a baroreceptor area results in a reflex reduction of arterial blood pressure (2), presumably owing to increased baroreceptor activity (5,(20)(21)(22)(23). The equivocal results of alterations of sympathetic activity to the carotid sinus (2, 7) and the lack of effect of intravenous infusion of norepinephrine (24) may well be due to the experiments' having been performed with an exposed sinus.…”

Section: Aortic Nerve Activitymentioning

confidence: 99%

Effects of Altered Smooth Muscle Tone on Aortic Diameter and Aortic Baroreceptor Activity in Anesthetized Rabbits

Aars

1971

Circulation Research

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The possible role of aortic smooth muscle in the regulation of aortic diameter and activity in the aortic baroreceptors was investigated in anesthetized rabbits. Aortic diameter was measured with ultrasonic technique within the intact thorax, and activity recorded in the whole left aortic nerve was quantified by rectification and integration. Blood pressure was changed by bleeding and reinfusion. At comparable blood pressures, norepinephrine (1 to 6 /ig/kg-min) produced a 1% to 10% constriction of the aorta, without affecting the pressure-strain elastic modulus (E P ). After phenoxybenzamine, maximum increases in diameter and E p were 17% and 280%, respectively. When related to diastolic diameter, however, E p was mostly increased by norepinephrine and reduced by phenoxybenzamine. Baroreceptor activity at comparable pressures remained normal during infusion of norepinephrine, but increased after phenoxybenzamine. However, when compared at equal diastolic diameters, the sensitivity of the receptors to aortic distention was found to be increased by norepinephrine and unaltered by phenoxybenzamine. Increased smooth muscle tone therefore served to maintain a normal relationship between blood pressure and baroreceptor activity, in spite of the simultaneous reduction in aortic diameter. Reduction of smooth muscle tone markedly increased activity in the aortic baroreceptors, due to dilatation of the receptor area. KEY WORDS phenoxybenzaminevascular smooth muscle modulus of elasticity norepinephrine • One possible way for the central nervous system to exercise control over the arterial baroreceptors might be through changing the tone of the vascular smooth muscle in the receptor area. This theory has been studied with different methods and with various results by several workers (1-8). However, none of them has been able to study the question in an undisturbed, unexposed baroreceptor area during a physiological contraction of the smooth muscle coat. It is the object of the present work to test whether in such circumstances dimensions and elasticity of MethodsTwenty rabbits weighing from 3.0 to 3.9 kg were used in the experiments. Three had arterial hypertension of renal origin (9). The animals were anesthetized with 3 ml 1% chloralose and 3 ml 25% urethan per kg. One-half the total amount was given intravenously, the rest intraperitoneally. When necessary, urethan was supplemented 254

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Section: Aortic Nerve Activitymentioning

confidence: 99%

Effects of Altered Smooth Muscle Tone on Aortic Diameter and Aortic Baroreceptor Activity in Anesthetized Rabbits

Aars

1971

Circulation Research

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“…Administration of vasopressin (VP) was reported to increase the frequency of both large and small amplitude spikes 4. Later studies supported the finding that NE affected mainly small amplitude spikes 5,6. More recently investigators have disagreed with this view.…”

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confidence: 85%

Effect of norepinephrine and vasopressin on carotid sinus baroreceptor activity in the anesthetized rabbit

Holmes

Ledsome

1984

Experientia

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Norepinephrine (NE) 10(-6) M or vasopressin (VP) 12.5 microU/ml were injected into the isolated carotid sinus of anesthetized rabbits. The sinus was exposed either to the arterial pressure or to a pressure controlled reservoir. Multifiber and single fiber recordings were made. Both NE and VP increased baroreceptor activity at all sinus pressures but decreased activity in a few fibers. The results are consistent with the drugs having their effects on smooth muscle fibers in the adventitia.

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Die Durchmesser-Druck-Beziehung des intakten Gef��gebietes der A. carotis communis von Katzen

Leitz

Arndt

1968

Pfl�gers Arch.

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Chemoreception und lokale Adrenalinwirkung am sinus caroticus

Cited by 9 publications

References 14 publications

Effects of Altered Smooth Muscle Tone on Aortic Diameter and Aortic Baroreceptor Activity in Anesthetized Rabbits

Effects of Altered Smooth Muscle Tone on Aortic Diameter and Aortic Baroreceptor Activity in Anesthetized Rabbits

Effect of norepinephrine and vasopressin on carotid sinus baroreceptor activity in the anesthetized rabbit

Die Durchmesser-Druck-Beziehung des intakten Gef��gebietes der A. carotis communis von Katzen

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