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Isolation of Human Atrial Myocytes for Simultaneous Measurements of Ca2+ Transients and Membrane Currents
10:53

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Published on: July 3, 2013

A cardioactive factor in human plasma with positive inotropic and positive chronotropic activities

S M Kalman1, R M Jones

  • 1Department of Pharmacology, Stanford University, Stanford, California 94305.

Proceedings of the National Academy of Sciences of the United States of America
|November 1, 1980
PubMed

Insights

Researchers discovered a cardioactive factor in human plasma that increases heart contraction and rate. This factor, with a molecular weight of 100,000, shows linked inotropic and chronotropic activities during purification.

Area of Science:

  • Cardiovascular Physiology
  • Biochemistry

Background:

  • Human plasma contains various bioactive molecules affecting cardiac function.
  • Understanding endogenous cardioactive substances is crucial for cardiovascular research.

Purpose of the Study:

  • To identify and characterize a novel cardioactive factor present in human plasma.
  • To investigate the properties and potential molecular nature of this factor.

Main Methods:

  • Purification of the cardioactive factor using cation- and anion-exchange chromatography, gel filtration, and polyethylene glycol precipitation.
  • Assessment of cardioactive properties using isolated guinea pig atria to measure positive inotropic and chronotropic effects.

Main Results:

  • A cardioactive factor with a molecular weight of approximately 100,000 was isolated from human plasma.
  • The factor demonstrated significant positive inotropic (increased contractility) and positive chronotropic (increased heart rate) activities.
  • The inotropic activity was found to be less stable than the chronotropic activity.
  • Both activities co-eluted during various chromatographic and precipitation steps, suggesting a linked or complex nature.

Conclusions:

  • Human plasma contains a substantial cardioactive factor influencing cardiac contractility and rate.
  • The factor's properties suggest it may be a large polypeptide or a protein complex.
  • Further research is needed to elucidate the precise molecular structure and physiological role of this cardioactive factor.

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