The nucleotide component of mammalian cardiac muscle

Beattie, Florence; Milroy, T. H.; Strain, Robert William Magill

doi:10.1042/bj0280084

Cited by 6 publications

(3 citation statements)

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“…ATP) (Lohmann & Schuster, 1934; Umschweif & Gibaylo, 1937). In cardiac muscle, ATP exists in combination with adenosinediphosphate (ADP), forming a dinucleotide (Embden, 1932;Beattie, Milroy & Strain, 1934;Ostern, 1934), but there is no evidence that this dinucleotide differs significantly from the mononucleotide ofvoluntary muscle in its physiological properties. The separate NUCLEOTIDE ETC., IN HEART estimation of adenosine and pyrophosphate should likewise give an indication of the distribution of the nucleotide complex in the heart.…”

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The distribution of nucleotide, phosphocreatine and glycogen in the heart

Davies¹,

Francis²,

Stoner³

1947

The Journal of Physiology

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It has been shown (e.g. Davies & Francis, 1941a) that, contrary to common belief, the hearts of poikilothermal vertebrates (fish, Amphibia, reptiles) are devoid of those specialized muscular tissues-nodal and Purkinje tissues that are responsible for the initiation and propagation of the stimulus for contraction in the hearts of mammals and birds, and that in each of these coldblooded animals the musculature of the heart has the same histological characters throughout its several chambers. Nevertheless, when each chamber of the heart is separated from its neighbours it will continue to contract, but at a different rate from the others. This phenomenon is not confined to the poikilothermal vertebrates, and it is well known that the chambers of the mammalian heart beat at different intrinsic rhythms when the specialized tissues are inactivated. Since these different rhythmical rates cannot be explained on an anatomical basis, the possibility of chemical differences in the muscle fibres has been explored.The role of adenosinetriphosphate (ATP) in the contraction of voluntary muscle has been established as a result of the work of Meyerhof, Parnas and their schools (for review, see Lipmann (1941)) and more recently of SzentGy6rgyi (1942SzentGy6rgyi ( , 1943. The ATP content of voluntary muscle cannot be directly estimated, but an indication of its distribution can be obtained by estimating separately adenosine and pyrophosphate, since these substances do not exist in the free state but only in combination as adenine nucleotide (e.g. ATP) (Lohmann & Schuster, 1934; Umschweif & Gibaylo, 1937). In cardiac muscle, ATP exists in combination with adenosinediphosphate (ADP), forming a dinucleotide (Embden, 1932;Beattie, Milroy & Strain, 1934;Ostern, 1934), but there is no evidence that this dinucleotide differs significantly from the mononucleotide ofvoluntary muscle in its physiological properties. The separate NUCLEOTIDE ETC., IN HEART estimation of adenosine and pyrophosphate should likewise give an indication of the distribution of the nucleotide complex in the heart. In voluntary muscle, ATP is present as the magnesium salt (Szent-Gy6rgyi, 1943; Biel- Gaddie & Stewart (1938). METHODSHearts from the frog, pigeon, rabbit and ox were used. Except where specially mentioned, the rabbits and pigeons were killed by a blow on the head and the frogs were pithed. The results have been expressed in mg./g. wet weight. Owing to the small amounts of tissues available, it was not possible to determine the dry weight in each analysis. The water content of the atria and ventricles has, however, been determined in a separate series of animals for each species, and the differences between the two chambers were found to be negligible in every case.Nudleotide estimations. In the frog, the heart was perfused (in situ) with isotonic NaCl solution and the ventricle and atria removed in one piece and dropped on to filter paper; the atria were then cut apart from the ventricle and each of these two segments was weighed on a torsion balance ...

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confidence: 99%

The distribution of nucleotide, phosphocreatine and glycogen in the heart

Davies¹,

Francis²,

Stoner³

1947

The Journal of Physiology

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“…In heart, it was first observed by Embden (81) and later confirmed by Beattie (19) and by Ostern (222) that there is a nucleotide with the composition of a diadenosine pentaphosphate, an extremely labile complex, which, except under special precautions, easily breaks down to a mixture of ADP and ATP. So easily does this happen that its existence was denied altogether by Lohmann and Schuster (186).…”

Section: Nomenclaturementioning

confidence: 94%

“…These compounds were identified, as usual, on the basis of ultraviolet spectra, phosphate content, reactivity, enzymatic digestion, etc. The structure of CMP is shown in figure 19. Acid-soluble extracts of thymus have shown the presence of the corresponding deoxyribose compounds (240) at all three levels of phosphorylation.…”

Section: Cdp Cholinementioning

confidence: 99%