Effect of Sodium Pentobarbital on the SA Nodal Activity of the Dog Heart &lt;i&gt;in vivo&lt;/i&gt;

Chiba, Shigetoshi; Nakajima, Tamio

doi:10.1620/tjem.106.381

Cited by 8 publications

(4 citation statements)

References 4 publications

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“…However, this finding is in keeping with a previous observation in patients who were already anesthetized (24). In the present study, the donor dogs were ventilated mechanically with background anesthesia of pentobarbital that could atten-1987;66:711-8 uate vagal tone and maintain heart rate at higher levels (25,26). Therefore, under the conditions of this study reflex tachycardia may be concealed by both baseline anesthesia and an opposing bradycardic action of midazolam.…”

Section: Discussionsupporting

confidence: 89%

Pharmacologic Basis of Responses to Midazolam in the Isolated, Cross-Perfused, Canine Right Atrium

Saegusa

Furukawa

Ogiwara

et al. 1987

Anesthesia & Analgesia

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CHIBA S. Pharmacologic basis of responses to midazolamin the isolated, cross-perfused, canine right atrium. 1987;66:711-8.The effects of midazolam on atrial rate and contractileforce in the isolated canine atrium perfused with donor blood were investigated. When midazolam in a dose range of 100-1000 pg was injected directly into the sinus node artery of the isolated atrium, biphasic (negative followed by positive) chronotropic and triphusic (positive, negative followed by positive) inotropic effects were induced. After propranolol or imipramine, the positive chronotropic and the ~econdary positive inotropic effects were significantly suppressed, but the initial positive inotropic effect was not affected. Tetrodotoxin, atropine, or R05-4864, a selective ligand for peripheral benzodiazepine binding sites, did not modify midazolam-induced effects. When midatolam in a dose of0.1-2 mglkg was administered intravenously to the donor dog, monophasic negative chronotropic and inotropic effects in the isolated atrium wereobserved but were not as prominent. We conclude that midazolam has direct cardiac inhibitory properties including catecholamine release due to a tyramine-like action.

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Section: Discussionsupporting

confidence: 89%

Pharmacologic Basis of Responses to Midazolam in the Isolated, Cross-Perfused, Canine Right Atrium

Saegusa

Furukawa

Ogiwara

et al. 1987

Anesthesia & Analgesia

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“…Other studies have indicated that the drug blocks ganglionic and peripheral sympathetic endings (Trethewie, 1953;Exley, 1954) and transmission in the nerve fibre (Toman, 1952). Other work reveals a direct effect of pentobarbitone Na on the heart, since a negative chronotropic effect of this anaesthetic has been reported on the isolated atrium of the guinea-pig in concentrations of 0.01 to 0.1 mg/ml (Schaer, 1964) or during perfusion of the artery of the Keith-Flack node (Chiba & Nakajima, 1972) in concentrations of 30 lg to 1Omg/ml. Urthaler et al (1974) in perfusions of both the artery of the SA node.…”

Section: Discussionmentioning

confidence: 96%

Influence of Chloralose and Pentobarbitone Sodium on Atrioventricular Conduction in Dogs

Duchêne-Marullaz¹,

Fabry-Delaigue²,

Gueorguiev³

et al. 1982

British J Pharmacology

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Atrial pacing at progressively increasing frequencies was performed on unanaesthetized dogs through electrodes placed aseptically in the wall of the right atrium and exteriorized in the neck region. Heart rate and two atrioventricular conduction (AVC) parameters, namely the Wenckebach Point (one or two systole block at the end of expiration)‐and the maximum atrioventricular conduction frequency (the frequency of pacing for which ventricles do not follow any auricular stimulation) were measured by electrocardiography. Chloralose (0.08 g/kg i.v.) did not affect either heart rate or AVC but significantly reduced the effect of atropine (0.1 mg/kg i.v.) on all three parameters measured. The effect of isoprenaline (0.25 μg kg−1 min−1) remained unchanged. Pentobarbitone Na (25 mg/kg i.v.) increased heart rate and usually caused the Wenckebach Point to disappear. It reduced the effects of atropine but did not modify those of isoprenaline. In view of these results we suggest that pentobarbitone Na be avoided as an anaesthetic agent in AVC studies. It is possible to dispense with an anaesthetic agent if the technique described here is used.

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“…This study shows that at doses causing a severe hypotension in donor dogs, pentobarbital did not produce direct negative chrono-or inotropic effects. Furthermore, it was demonstrated that pentobarbital has a dominant negative inotropic effect compared to its negative chronotropic one in the isolated canine atrial preparation (2). It was also shown that in the isolated canine ventricular preparation, pentobarbital induced a strong negative inotropic effect in a dose-related manner with extremely large doses (6).…”

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confidence: 98%

“…Since pentobarbital caused a bradycardia when injected selectively into the cannulated sinus node artery in the isolated atrium and in vivo heart of the dog (1,2), it was recognized that it has direct depressant properties on the sinoatrial (SA) node. However, it is still not precisely clear whether pentobarbital in concentrations that induced an adequate anesthesia influences the SA nodal pacemaker activity.…”

mentioning

confidence: 99%

Dominant Anti-vagal Effect of Pentobarbital on Cardiac Responses to Intracardiac Autonomic Nerve Stimulation in the Dog

Chiba

Tsuboi

2001

Japanese Journal of Pharmacology

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ABSTRACT-The isolated canine atrium was perfused by heparinized blood of the donor dog. An adequate dose of pentobarbital that induced a potent hypotension in the donor did not produce any significant change in the atrial rate and developed tension in the isolated atrium perfused with donor's blood. Pentobarbital in doses that modified neither cardiac responses to intracardiac adrenergic nerve stimulation nor exogenously given norepinephrine or acetylcholine significantly inhibited intracardiac vagal responses. From these results, it is concluded that a large dose of pentobarbital has a dominant antivagal effect in the heart.

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Effect of Sodium Pentobarbital on the SA Nodal Activity of the Dog Heart <i>in vivo</i>

Cited by 8 publications

References 4 publications

Pharmacologic Basis of Responses to Midazolam in the Isolated, Cross-Perfused, Canine Right Atrium

Pharmacologic Basis of Responses to Midazolam in the Isolated, Cross-Perfused, Canine Right Atrium

Influence of Chloralose and Pentobarbitone Sodium on Atrioventricular Conduction in Dogs

Dominant Anti-vagal Effect of Pentobarbital on Cardiac Responses to Intracardiac Autonomic Nerve Stimulation in the Dog

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