Adenosine attenuates C-terminal but not N-terminal proteolysis of cTnI during cardioplegic arrest

William R. Law, James Ross, Zivojin S. Jonjev

Research output: Contribution to journalArticle

1 Citation (Scopus)

Abstract

Specific site proteolysis and loss of troponin I (TnI) during myocardial ischemic events can contribute to myocardial dysfunction. Adenosine supplementation of cardioplegic solutions results in improved functional preservation of the heart. We investigated the effect of adenosine on N-terminal and C-terminal proteolysis of TnI in the heart. Hearts from male Sprague-Dawley rats were isolated and perfused at a constant pressure. Cardioplegic arrest (St. Thomas #2 ± 100 μm adenosine) was induced and hearts frozen at various times during the arrest. Antibodies directed against specific regions of TnI were used to visualize TnI in whole heart homogentates, as well as from cellular fractions, using western blot analysis. Cardioplegic arrest alone resulted in early N-terminal proteolysis of TnI, followed by later loss of sequences from the C-terminal end of the molecule. In addition, secondary protein bands that were immunoreactive to amino acid sequences centrally located on the TnI molecule were observed. There was also evidence of dissociation of TnI from the other myofibrillar proteins. The supplementation of cardioplegic solution with adenosine significantly attenuated the late C-terminal proteolytic degradation of TnI and its apparent dissociation from myofibrils proteins but had no effect on the early N-terminal proteolysis associated with cardioplegic arrest. These data may provide an explanation for partial protection against postarrest myocardial dysfunction provided by adenosine.

Original languageEnglish (US)
Pages (from-to)126-133
Number of pages8
JournalJournal of Surgical Research
Volume123
Issue number1
DOIs
StatePublished - Jan 2005
Externally publishedYes

Fingerprint

Troponin I
Adenosine
Proteolysis
Cardioplegic Solutions
Proteins
Myofibrils
Sprague Dawley Rats
Amino Acid Sequence
Western Blotting
Pressure
Antibodies

Keywords

  • cardiac arrest
  • cardiac surgery
  • myocardial function
  • proteolysis
  • troponin I

ASJC Scopus subject areas

  • Surgery

Cite this

Adenosine attenuates C-terminal but not N-terminal proteolysis of cTnI during cardioplegic arrest. / Law, William R.; Ross, James; Jonjev, Zivojin S.

In: Journal of Surgical Research, Vol. 123, No. 1, 01.2005, p. 126-133.

Research output: Contribution to journalArticle

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