Skip to main content
PMC home page
Biophysical Journal logoLink to Biophysical Journal
. 1977 Oct;20(1):33–48. doi: 10.1016/S0006-3495(77)85535-5

An osmometer model for changes in the buoyant density of chromaffin granules.

S J Morris, H A Schultens, R Schober
PMCID: PMC1473339  PMID: 901901

Abstract

We present a model for the structure of isolated bovine adrenal medulla chromaffin granules derived from the dependence of granule density on the osmotic pressure of the suspension medium at 2 degrees C. The granule consists of a flexible, inelastic membrane bounding an osmotically active core. The core consists of a solution space and a separate, nonosmotic phase. Since the granule behaves like a "perfect" osmometer over a wide range of osmolarities, we conclude that (a) within these limits, the core consists of a constant amount of condensed material and a constant number of particles in solution, (b) from the constraints of the osmometer model, the osmolality inside the granule must equal the osmolality outside. Therefore the high concentrations of catecholamines (greater than 0.7 M) and ATP (greater than 0.18 M) measured biochemically cannot be dissolved in the core solution as separate molecules, but must be condensed into larger aggregates. These results are supported by electron micrographic examination of the effect of osmotic pressure changes on granule morphology.

Full text

PDF
33

Images in this article

44FIGURE 5
on p.44

Selected References

These references are in PubMed. This may not be the complete list of references from this article.

  1. CARLSSON A., HILLARP N. A. On the state of the catechol amines of the adrenal medullary granules. Acta Physiol Scand. 1958 Nov 18;44(2):163–169. doi: 10.1111/j.1748-1716.1958.tb01618.x. [DOI] [PubMed] [Google Scholar]
  2. Dolais-Kitabgi J., Perlman R. L. The stimulation of cathecholamine release from chromaffin granules by valinomycin. Mol Pharmacol. 1975 Nov;11(6):745–750. [PubMed] [Google Scholar]
  3. Dowdall M. J., Boyne A. F., Whittaker V. P. Adenosine triphosphate. A constituent of cholinergic synaptic vesicles. Biochem J. 1974 Apr;140(1):1–12. doi: 10.1042/bj1400001. [DOI] [PMC free article] [PubMed] [Google Scholar]
  4. HILLARP N. A. Further observations on the state of the catechol amines stored in the adrenal medullary granules. Acta Physiol Scand. 1959 Nov 15;47:271–279. doi: 10.1111/j.1748-1716.1960.tb00078.x. [DOI] [PubMed] [Google Scholar]
  5. Johnson R. G., Scarpa A. Internal pH of isolated chromaffin vesicles. J Biol Chem. 1976 Apr 10;251(7):2189–2191. [PubMed] [Google Scholar]
  6. Kirshner N., Holloway C., Kamin D. L. Permeability of catecholamine granules. Bibl Laeger. 1966 Mar 14;112(3):532–537. doi: 10.1016/0926-6585(66)90256-1. [DOI] [PubMed] [Google Scholar]
  7. Lagercrantz H., Pertoft H., Stjärne L. Facts and artifacts in gradient centrifugation analysis of catecholamine granules. Acta Physiol Scand. 1970 Apr;78(4):561–566. doi: 10.1111/j.1748-1716.1970.tb04692.x. [DOI] [PubMed] [Google Scholar]
  8. Morris S. J., Schober R., Schultens H. A. Correlation of physical and morphological parameters with release of catecholamines, ATP, and protein from adrenal medulla chromaffin granules. Biochim Biophys Acta. 1977 Jan 4;464(1):65–81. doi: 10.1016/0005-2736(77)90371-6. [DOI] [PubMed] [Google Scholar]
  9. Morris S. J., Schovanka I. Some physical properties of adrenal medulla chromaffin granules isolated by a new continuous iso-osmotic density gradient method. Biochim Biophys Acta. 1977 Jan 4;464(1):53–64. doi: 10.1016/0005-2736(77)90370-4. [DOI] [PubMed] [Google Scholar]
  10. Papadopoulou-Daifotis Z. P., Morris S. J. Differential lysis of adrenaline- and noradrenaline-containing chromaffin granules promoted by the ionophore Br X537A. Neuroscience. 1977;2(4):609–619. doi: 10.1016/0306-4522(77)90058-6. [DOI] [PubMed] [Google Scholar]
  11. Perlman R. L. The permeability of chromaffin granules to non-electrolytes. Biochem Pharmacol. 1976 May 1;25(9):1035–1038. doi: 10.1016/0006-2952(76)90492-5. [DOI] [PubMed] [Google Scholar]
  12. Phillips J. H., Allison Y. P., Morris S. J. The distribution of calcium, magnesium, copper and iron in the bovine adrenal medulla. Neuroscience. 1977;2(1):147–152. doi: 10.1016/0306-4522(77)90075-6. [DOI] [PubMed] [Google Scholar]
  13. Pletscher A., Da Prada M., Berneis K. H., Steffen H., Lütold B., Weder H. G. Molecular organization of amine storage organelles of blood platelets and adrenal medulla. Adv Cytopharmacol. 1974;2:257–264. [PubMed] [Google Scholar]
  14. Trifaró J. M., Dworkind J. A new and simple method for isolation of adrenal chromaffin granules by means of an isotonic density gradient. Anal Biochem. 1970 Apr;34(2):403–412. doi: 10.1016/0003-2697(70)90125-9. [DOI] [PubMed] [Google Scholar]

Articles from Biophysical Journal are provided here courtesy of The Biophysical Society

RESOURCES