Adrenergic Mechanism of Vagal Cardiostimulation

Middleton, Samuel; Middleton, H. H.; Tohá, J.

doi:10.1152/ajplegacy.1949.158.1.31

Cited by 28 publications

(10 citation statements)

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“…There is some evidence that acetylcholine released by stimulation of cardiac preganglionic vagal fibers may cause excitation of intracardiac adrenergic structures (6,7). If the cardiac augmentation observed in our experiments were the manifestation of such a mechanism, the administration of an anticholinesterase would be expected to potentiate the observed responses.…”

Section: Recordings From the Bilateral Isovolumetric Preparation Withmentioning

confidence: 61%

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Responses of Individual Cardiac Chambers to Stimulation of the Cervical Vagosympathetic Trunk in Atropinized Dogs

Randall

Pace

et al. 1967

Circulation Research

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Employing multiple chamber pressure recording techniques, the presence of fibers within the right and left cervical vagosympathetic trunks which innervate both right and left ventricles has been demonstrated. Electrical excitation of the cervical vagosympathetic in the atropinized dog elicited a distinct increase in both rate of rise and in maximal systolic intraventricular pressures, with or without cardiac acceleration. It persisted during electrical pacing of the right ventricle. In many animals, the a-wave of the atrial pressure traces also showed augmentation, but this was not consistent or essential for the ventricular response. Although pulmonary vasoconstriction was not ruled out as a concurrent event, its contribution to right ventricular augmentation was not essential as demonstrated in bilateral, isovolumetric ventricular preparations. The evidence indicates the presence of adrenergic fibers in the cervical vagosympathetic trunk which are distributed to all four cardiac chambers. Their effects on the heart are abolished by the /3-blocking agent, propranolol, and are unaffected by eserine administration.

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Section: Recordings From the Bilateral Isovolumetric Preparation Withmentioning

confidence: 61%

“…Middleton and his associates have reported augmented contractility in the atropinized, isolated heart during vagal stimulation and during acetylcholine infusions, implicating excitation of intracardiac sympathetic structures by liberated acetylcholine (6,7). Similar observations have been reported by others (8,9), most recently by Hollenberg et al (10).…”

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confidence: 60%

Responses of Individual Cardiac Chambers to Stimulation of the Cervical Vagosympathetic Trunk in Atropinized Dogs

Randall

Pace

et al. 1967

Circulation Research

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“…The after-posi tivity sometimes observd immediately after the interruption of vagal stimulation was abolished by the pretreatment of guinea-pig with reserpine but not by DCI in the con centration of 10-'. Middleton et al (23) have reported that the adrenaline-like substance is released in the perfusion fluid of the cat's heart during vagal stimulation. The result that the after-positivity was not affected by DCI may be attributed to the concentra tion of the drug applied in the present experiment, being enough to block the effect of added amines but not enough to antagonize the adrenaline-like substance released by vagal stimulation.…”

Section: Discussionmentioning

confidence: 99%

Effects of the Adrenergic Drugs on the Chrono- And Inotropic Responses to the Cholinergic Stimulation of the Isolated Guinea-Pig’s Atria

Toda

Fujiwara

Shimamoto

1964

Japanese Journal of Pharmacology

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Hukovic (1) was the first to suggest the existence of the cholinergic fibers in the sympathetic nerve of the rabbit's atria. He showed that stimulation of the sympathetic nerve in the isolated reserpinized heart produced the negative chrono and inotropic effects which were potentiated by eserine and abolished by atropine. A series of ex periments in this laboratory (2-5) have excluded an essential role of the heart cate cholamine on initiation and maintenance of the spontaneous contraction and action potential of the rabbit's atria. Recently, Misu (6, 7) and Misu and Takaori (8) in this laboratory have demonstrated that the atrial action potentials abolished by the con centration of 10-5 of dibenarnine, chlorpromazine and yohimbine, are restarted by ad renaline as well as by acetylcholine, and that noradrenaline mainly shortens the repo larization phase of the potential, while acetylcholine serves to restore the depolariza tion phase. This suggests a modulating role of the endogenous noradrenaline in the rhythmic contraction or action potential of the heart, and led us to study the effects of catecholamine-relating drugs on the atrial responses to cholinergic stimulation. METHODSThe isolated atria of guinea-pig, weighing 250 to 350 g and of either sex, were mainly used. In some of the experiments the isolated atria of rabbit, weighing 1.8 to 2.2 kg, were also used.Preparation of the isolated atria attached with innervated vagus nerves : The animal was fixed on the animal-board in a supine position, and after longitudinal incision in the neck the right and left vagus nerves and carotid arteries were separated from the sur rounding connective tissues toward the entrance of the nerves and arteries into the thorax. Immediately after a full exsanguination by cutting both carotid arteries the thorax was opened and the atria with the vagus nerves were prepared following sur gical procedures described previously (9). Spontaneous contraction of the atria in the

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“…Middleton, Middleton, and Toha (1949) have shown that vagus stimulation liberates an adrenalinelike substance from the isolated heart after treatment with atropine, so that the acceleration occurs after a physiological stimulus as well as when nicotine or large doses of acetylcholine are applied. Our experiments show that the stimulant action of nicotine and acetylcholine is present after degeneration of the sympathetic fibres, and is therefore probably related to this vagus acceleration.…”

Section: Discussionmentioning

confidence: 99%

Nicotine‐like Actions in Auricles and Blood Vessels After Denervation

Ginzel

Kottegoda

1953

British Journal of Pharmacology and Chemotherapy

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The work to be described in this paper is a continuation of observations made on the action of nicotine and acetylcholine in the isolated auricles of the rabbit heart and in the perfused vessels of the rabbit ear (Kottegoda, 1953a(Kottegoda, , 1953b. Nicotine and acetylcholine were found to stimulate the auricles in the presence of atropine, and the stimulant action was blocked by hexamethonium. Similarly nicotine was found to constrict the vessels of the rabbit ear; acetylcholine in the presence of atropine or when the perfusion had continued for 24 hours had the same effect. This constrictor action was blocked by hexamethonium; in the presence of benzylimidazoline (Priscol) the constrictor action was reversed to a dilator action, and this dilator action was also blocked by hexamethonium. The observations suggested that the actions of nicotine and of acetylcholine were indirect and were due to the liberation of an adrenaline-like substance. Because of these and various other findings discussed later further experiments were undertaken to test the action of nicotine and acetylcholine on auricles and on vessels which had been denervated some time previously.For experiments on auricles, cats were used in place of rabbits, as the former were found to stand the operation better. A few auricles from normal cats were tested with nicotine and acetylcholine in the presence of atropine; it was found that they behaved like rabbit auricles towards these substances. METHODSCat Auricles. Both stellate ganglia were removed from cats under ether and pentobarbitone sodium (30 mg./kg. body weight intraperitoneally). After 12 to 14 days the animals were killed, the auricles dissected out, and the response to acetylcholine and nicotine tested according to the method described earlier (Kottegoda, 1953a).

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Adrenergic Mechanism of Vagal Cardiostimulation

Cited by 28 publications

References 0 publications

Responses of Individual Cardiac Chambers to Stimulation of the Cervical Vagosympathetic Trunk in Atropinized Dogs

Responses of Individual Cardiac Chambers to Stimulation of the Cervical Vagosympathetic Trunk in Atropinized Dogs

Effects of the Adrenergic Drugs on the Chrono- And Inotropic Responses to the Cholinergic Stimulation of the Isolated Guinea-Pig’s Atria

Nicotine‐like Actions in Auricles and Blood Vessels After Denervation

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