Adrenergic receptors in the veins of the dog

Guimarães, S.; Osswald, Walter

doi:10.1016/0014-2999(69)90021-1

Cited by 108 publications

(27 citation statements)

References 4 publications

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“…Using the technique of selective receptor protection described by Furchgott (1954) on strips of rabbit aorta, Innes (1962) first demonstrated that the stimulant action of ergotamine on the smooth vascular muscles is mediated at least in part by a-adrenoceptors. These findings were largely confirmed by other studies on isolated canine veins (Guimaraes & Osswald, 1969), perfused hind limb of the dog (Osswald, Guimaraes & Garret, 1970), isolated spleen and nictitating membrane of the cat (Salzmann, Pacha, Taeschler & Weidmann, 1968) and on vertebrate melanophores (Goldman & Hadley, 1970 In each series of experiments vein strips from six dogs of either sex were used. The mean age of the dogs was 5 (2-9) years and their mean body weight was 30 (15-40) kg.…”

supporting

confidence: 67%

Investigations on the Mode of Action of Ergotamine in the Isolated Femoral Vein of the Dog

Müller‐Schweinitzer¹,

Stürmer²

1974

British J Pharmacology

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1Experiments on spiral strips cut from the femoral vein of dogs suspended in Krebs-Henseleit solution were carried out. 2 Ergotamine caused stimulation in concentrations about 350 times lower than noradrenaline (ED50 of ergotamine = 2.2 x 10-9 M; ED50 of noradrenaline = 7.6 x 10-7 M), but the maximal responses to ergotamine were only about one third those to noradrenaline. 3 The pA2 value of ergotamine against noradrenaline was 8.8. 4 The effects of ergotamine can be blocked by prior administration of phentolamine. The pA2 value for phentolamine against ergotamine was 6.8 and the pA2 value for phentolamine against noradrenaline was 7.5. 5 It is concluded that the stimulant action of ergotamine on smooth vascular muscle probably is mediated mainly via at-adrenoceptors.

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supporting

confidence: 67%

Investigations on the Mode of Action of Ergotamine in the Isolated Femoral Vein of the Dog

Müller‐Schweinitzer¹,

Stürmer²

1974

British J Pharmacology

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“…role, for a-adrenergic stimulants are known to cause venoconstriction (6). In fact, prazosin was demonstrated to reduce the venous return in our previous study using the same preparation as that of the present study (7).…”

supporting

confidence: 58%

Effect of carvedilol on venous return: A mechanism of reduction in blood pressure.

et al. 1991

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ABSTRACT-We studied the effect of carvedilol, a ~Q-blocker with a potent a-blocking activity, on venous return in anesthetized dogs. Though 3,ug/kg of carvedilol caused a slight increase in blood pressure and total peripheral resistance, these changes disappeared by further doses of the agent. On the other hand, each dose of carvedilol (3 -100 ,a g/kg) decreased venous return significantly and dose-dependently. These results indicate that the hypotensive effect of carvedilol mainly depends on the decrease in venous return rather than arterial vasodilation.

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“…/3-Adrenoceptors Six preparations were maximally contracted with noradrenaline and when the response reached a steady plateau an ED50 contracting dose of isoprenaline was added according to the method used by Guimaraes & Osswald (1969). The selection of doses was determined from dose response curves.…”

Section: Resultsmentioning

confidence: 99%

“…Clement, Vanhoutte & Leusen (1969) also found that phentolamine (20 yg/ml) completely blocked isoprenaline induced contractions of the dog isolated lateral saphenous and mesenteric veins (by recording isobaric volume changes). Guimaraes & Osswald (1969) have shown that phenoxybenzamine (370 ng/ml-7-4 jug/ml) and ergotamine (7-5 ng/ml-680 ng/ml) not only caused blockade of isoprenaline contractions of the dog isolated lateral saphenous vein but also caused reversal of the response (relaxation) according to the degree of tone in the tissue strips. Other authors have reported slight relaxation The potencies of isoprenaline are expressed as the molar concentration causing 50% contractions and relative to noradrenaline.…”

Section: Discussionmentioning

confidence: 99%

The effect of isoprenaline on adrenoceptors in human saphenous vein

Coupar¹

1970

British J Pharmacology

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Sunmary1. The order of potency of sympathomimetic amines in causing contraction of strips of human saphenous vein was (-)-adrenaline>(-)-noradrenaline> (-)-phenylephrine>( ± )-isoprenaline.2. The competitive a-adrenoceptor blocking drugs tolazoline, phentolamine, and thymoxamine and the irreversible blocking drug phenoxybenzamine all blocked noradrenaline and isoprenaline contractions. 3. Contractions produced by 5-hydroxytryptamine were also blocked by phentolamine and thymoxamine. Fenfluramine-induced contractions were-not blocked by thymoxamine or phenoxybenzamine. 4. ED50 contracting doses of isoprenaline did not cause consistent relaxation of noradrenaline-contracted strips. 5. It is concluded that human saphenous vein contains a dominant population of a-adrenoceptors which can be stimulated by high doses of isoprenaline, but the occurrence of /3-adrenoceptors mediating relaxation is rare.

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Adrenergic receptors in the veins of the dog

Cited by 108 publications

References 4 publications

Investigations on the Mode of Action of Ergotamine in the Isolated Femoral Vein of the Dog

Investigations on the Mode of Action of Ergotamine in the Isolated Femoral Vein of the Dog

Effect of carvedilol on venous return: A mechanism of reduction in blood pressure.

The effect of isoprenaline on adrenoceptors in human saphenous vein

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