Catecholamine Depletion in Thyrotoxicosis

Goldstein, Sidney; Killip, Thomas

doi:10.1161/01.cir.31.2.219

Cited by 39 publications

(2 citation statements)

References 24 publications

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“…for further references), 1956 (in dogs); Wurtman, Kopin & Axelrod, 1963 (in rats)). It has also been suggested that increased background sympathetic activity may develop rather than sensitization of receptors, since heart rates in thyrotoxic patients and animals were immediately reduced by sympatholytic procedures (spinal anaesthesia (Brewster et al 1956); reserpine (Thier, Gravenstein & Hoffman, 1962); guanethidine (Goldstein & Killip, 1965); propranolol (Howitt & Rowlands, 1966); oxprenolol (Turner & Hill, 1968;Darsinos, Katsilambros, Papamatheou & Papadoyanakis, 1968)).…”

Section: Discussionmentioning

confidence: 99%

The effect of altered thyroid state on atrial intracellular potentials

Freedberg¹,

Papp²,

Williams³

1970

The Journal of Physiology

206

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SUMMARY1. A group of rabbits was made hypothyroid by thyroidectomy, and another group was injected daily with L-thyroxine. After an appropriate interval respective alterations in thyroid state were confirmed by measurement of heart weight and of plasma iodine, and the animals' atria were isolated for recording.2. Measurements were made of atrial contractions, conduction velocity, spontaneous heart rate and maximum driven frequency, and action potentials were recorded with intracellular micro-electrodes. 3. The resting potential and action potential heights were not affected by differences of thyroid state. 4. Atrial arrhythmias are common in hyperthyroidism, rare in myxoedema. The possibility that hypothyroidism might reduce the rate of rise of the action potential, as do anti-arrhythmic drugs, and hyperthyroidism increase it, was investigated. Although the rate of rise was slower in hypothyroid atria at some driving frequencies, this could not alone account for an anti-arrhythmic effect, because at frequencies near the spontaneous heart rate the rate of rise of the action potential was not reduced.5. The duration of the repolarization phase of the action potential was greatly prolonged in atria from thyroidectomized rabbits, and was shortened in hyperthyroid atria. These changes could account for a reduced probability of arrhythmias in hypothyroidism, and the converse in hyperthyroidism.

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Section: Discussionmentioning

confidence: 99%

The effect of altered thyroid state on atrial intracellular potentials

Freedberg¹,

Papp²,

Williams³

1970

The Journal of Physiology

206

View full text Add to dashboard Cite

show abstract

“…Previous reports have been exclusively concerned with the effect upon heart rate, blood pressure and cardiac output. A reduction of all these parameters has been almost uniformly achieved with Guanethidine, the currently most popular sympathetic ganglionic blocking agent (7, 9,14,32). Common to all the above-mentioned works is the lack of a normal control group.…”

Section: (26)mentioning

confidence: 99%