Der Calciumalternans

Kisch, Bruno

doi:10.1007/bf02609911

Cited by 16 publications

(17 citation statements)

References 8 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Atrial-specific granules (ASGs), described nearly three decades ago and present in the heart of most vertebrates (1,2), contain precursors of a family of vasodilator and natriuretic polypeptides, collectively called atrial natriuretic factor (ANF) (3)(4)(5)(6)(7). The heart can function as an endocrine organ, releasing ANF in response to changes in atrial distending pressure and other stimuli (8).…”

mentioning

confidence: 99%

Atrial-specific granules in situ have high calcium content, are acidic, and maintain anion gradients.

Somlyo

Broderick

Shuman

et al. 1988

Proc. Natl. Acad. Sci. U.S.A.

View full text Add to dashboard Cite

The composition and pH of atrial-specific granules of rat heart were determined by electron probe x-ray microanalysis and fluorescence microscopy, respectively. The high (75 mmol/kg of dry weight) calcium content and higher than cytoplasmic concentration of chloride in atrial-specific granules were visualized in high-resolution x-ray maps. The C1-content of granules and cytoplasm decreased and a bromide gradient (granule > cytoplasm) was established during incubation in low-chloride, NaBr-containing solutions.Scanning confocal fluorescence light microscopy of live atria incubated with acridine orange demonstrated dye accumulation, indicative of low intragranular pH. We conclude that the granules represent a hitherto unrecognized intracellular store of cardiac calcium and can develop and maintain an anion gradient, presumably through cotransport by means of a proton-pumping ATPase.Atrial-specific granules (ASGs), described nearly three decades ago and present in the heart of most vertebrates (1, 2), contain precursors of a family of vasodilator and natriuretic polypeptides, collectively called atrial natriuretic factor (ANF) (3-7). The heart can function as an endocrine organ, releasing ANF in response to changes in atrial distending pressure and other stimuli (8). We now show that ASGs share other properties of endocrine secretory granules, such as an acidic interior and the ability to establish a sizable anion gradient. We also show that these organelles have a high Ca content and are a hitherto unknown store of intracellular Ca in atrial myocardium. Based on the known sequences ofANF prohormone (9, 10) and the Ca-binding protein calsequestrin (11), we suggest that the high Ca content of ASGs is probably due to binding to grouped acidic residues in the aminoterminal sequence of the prohormone. METHODS AND MATERIALSMale Wistar rats (250-300 g of body weight) were killed by cervical dislocation, and the hearts were quickly excised and placed in a well-oxygenated modified Krebs/bicarbonate solution (pH 7.4) at 32°C containing (mM) NaCl, 125; KCI, 4.7; KH2PO4, 1.2; MgSO4, 1.2; NaHCO3, 18.7; CaCl2, 1.2; dextrose, 5.6. The right atrium was everted over a 1.5-mm (diameter) silver pin and tied at the base. Tension was not monitored. The atria in Krebs solution generally beat spontaneously up to the point of freezing in either systole or diastole. To determine whether ASGs can establish an anion gradient de novo, atria were incubated for 15 min at 32°C in a solution (pH 7.4) containing (mM) sodium methanesulfonate, 105; NaBr, 20; potassium methanesulfonate, 4.7;

show abstract

mentioning

confidence: 99%

Atrial-specific granules in situ have high calcium content, are acidic, and maintain anion gradients.

Somlyo

Broderick

Shuman

et al. 1988

Proc. Natl. Acad. Sci. U.S.A.

View full text Add to dashboard Cite

show abstract

“…The non-identity with cholinesterases has been suggested from distribution studies (KISCH, KOSTER and STRAUSS 1943), but such studies do not give any proof for the specificity of esterases. There is, however, no reason to suggest the presence of a specific esterase for procaine.…”

Section: Discussionmentioning

confidence: 98%

Protection of Cholinesterases by Procaine against Inactivation by Tabun in vitro.

Augustinsson

Grahn

1953

Acta Physiologica Scandinavica

View full text Add to dashboard Cite

It is known from previous reports that reversible "anticholinesterases" (physostigmine, prostigmine) protect cholinesterases against the irreversible enzyme inactivation by organophosphorus compounds (KOELLE 1946; AUGUSTINSSON and NACHMANSOHN 1949; BURGEN 1949; BAIN 1949). This has been demonstrated both in vitro and in vim. I n addition, acetylcholine protects the enzyme against such inactivation in vitro (AUGUSTINSSON and NACHMANSOHN 1949). These observations suggest that the organophosphorus compounds act on the same active centre of the enzyme molecule as acetylcholine. This centre, most probably, is the "esteratic" site (see review by NACHMANSOHN and WILSON 1951).

show abstract

“…Amino-terminal residues beyond the disulfide bridge are not necessary for biologic action; elongation at the amino terminus, however, to very large sequences, such as proatrin itself, is associated with loss of activity (45). Intracellular storage One of the early clues to the existence of an atrial secretory product was the finding of characteristic granules in myocytes of mammalian atria (46,47). These granules are clustered at the nuclear poles (47) and have histological staining properties unique to proteins (48).…”

Section: Molecular Structurementioning

confidence: 99%

Biologically active atrial peptides

1988

General and Comparative Endocrinology

View full text Add to dashboard Cite

Der Calciumalternans

Cited by 16 publications

References 8 publications

Atrial-specific granules in situ have high calcium content, are acidic, and maintain anion gradients.

Atrial-specific granules in situ have high calcium content, are acidic, and maintain anion gradients.

Protection of Cholinesterases by Procaine against Inactivation by Tabun in vitro.

Biologically active atrial peptides

Contact Info

Product

Resources

About