Method for measuring the contractions of small hearts in organ culture

Wildenthal, K.; Harrison, D. R.; Templeton, G. H.; Reardon, W

doi:10.1093/cvr/7.1.139

Cited by 4 publications

(3 citation statements)

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“…Measurements of cardiac contraction and glycogen content were made in Dallas by techniques described by Wildenthal et al (2,6) and Karlsson (7). Adenylate cyclase activity in fresh cardiac homogenates was measured in Indianapolis by techniques described below.…”

Section: Methodsmentioning

confidence: 99%

“…Recordings of contractions were obtained with a specially constructed microcapacitance-probe that has been described previously (6). The device detects movements in space of the isotonically beating hearts; changes in the speed and extent of displacement of the hearts can be recorded as a function of changes in inotropic state while beating rate is monitored simultaneously.…”

Section: Methodsmentioning

confidence: 99%

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Responsiveness to glucagon in fetal hearts. Species variability and apparent disparities between changes in beating, adenylate cyclase activation, and cyclic AMP concentration.

Wildenthal¹,

Allen²,

Karlsson³

et al. 1976

J. Clin. Invest.

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A B S T R A C T Previous studies of the ability of the immature heart to respond to glucagon have yielded conflicting results. To test the possibility that the apparent discrepancies might be explained in part by species variability, isolated hearts of fetal mice and rats (13-22 days' gestational age) were studied under identical conditions in vitro. Changes in atrial rate and ventricular contractility were measured in spontaneously beating hearts exposed to glucagon, and activation of adenylate cyclase was assayed in cardiac homogenates.In mice of 16 days' gestational age or less, there was no change in heart rate in response to glucagon; at 17-18 days, minimal responsiveness was present; and after 19 days, 10 AM glucagon caused an increase in spontaneous atrial rate of 30+4% (SEM) (P < 0.001). Measurement of the extent and speed of volume displacement of the isotonically contracting hearts with a specially constructed capacitance transducer revealed that ventricular inotropic responsiveness also appeared after 17-19 days. Cardiac stores of glycogen were reduced in older hearts exposed to glucagon, but not in those aged less than 16 days. In contrast, glucagon failed to activate adenylate cyclase in homogenates of hearts of fetal mice at any age. Furthermore, glucagon failed to elicit an increase in the concentration of cyclic

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Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Responsiveness to glucagon in fetal hearts. Species variability and apparent disparities between changes in beating, adenylate cyclase activation, and cyclic AMP concentration.

Wildenthal¹,

Allen²,

Karlsson³

et al. 1976

J. Clin. Invest.

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show abstract

“…The chamber was then transferred to a 370 water bath in room air where, over a period of 5-10 min, a doseresponse curve to the drug being evaluated was obtained. Previous studies have established that fetal mouse hearts prepared in the manner described beat in control media at a constant rate and with a constant amplitude of contraction for over 20 min or more after the chamber has been transferred to the water bath (4), so the duration of each experiment in the present study was well within the period of stability of the system. Dose-response curves relating spontaneous heart rate to the concentration of the drug being evaluated were obtained for 330 hearts by procedures described in a previous publication (5).…”

Section: Introductionmentioning

confidence: 90%

Maturation of Responsiveness to Cardioactive Drugs

Wildenthal¹

1973

J. Clin. Invest.

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A B STR A CT Freshly isolated hearts of fetal mice of gestational ages ranging betwveen 12 and 22 days (term) were exposed to several concenitrations of a variety of chronotropic agents. Acetylcholine (10-4-10-2 M) caused marked bradycardia in all hearts, even after only 12-14 days' gestation (i.e., even before cardiac innervation had occurred), and the intensity of the response increased steadily with advancing age throughlout gestation. Responsiveness to norepinephrinie was present but minimal at 12-14 days, so that mean atrial rate rose by < 10% with a maximal concentration of the drug (10-sM) ; responsiveness became more marked by [15][16]

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Toxins in open heart surgery

Longmore¹,

Smith²

1981

Towards Safer Cardiac Surgery

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Method for measuring the contractions of small hearts in organ culture

Cited by 4 publications

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Responsiveness to glucagon in fetal hearts. Species variability and apparent disparities between changes in beating, adenylate cyclase activation, and cyclic AMP concentration.

Responsiveness to glucagon in fetal hearts. Species variability and apparent disparities between changes in beating, adenylate cyclase activation, and cyclic AMP concentration.

Maturation of Responsiveness to Cardioactive Drugs

Toxins in open heart surgery

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