The effect of temperature on spontaneous action potential discharge of the isolated sinus venosus from winter and summer plaice (Pleuronectes platessa)

A. A. Harper, I. P. Newton, P. W. Watt

Research output: Contribution to journalArticlepeer-review

33 Citations (Scopus)

Abstract

The spontaneous cardiac pacemaker activity and conformation were recorded in vitro, using intracellular recording methods, from heart tissue of summer- and winter-caught plaice. The effects of changing temperature on the pacemaker rate, duration of action potential and diastolic depolarization were investigated by altering the temperature of the superfusing medium. The resting intrinsic rate of discharge was significantly greater in pacemaker cells from winter plaice (P=0.05), but there was no significant difference between winter and summer fish in the apparent Arrhenius activation energies for this process. However, there was a significant difference in the estimated intercept, indicating a thermal shift in the processes underlying the spontaneous pacemaker rhythm. There was no significant difference in the diastolic depolarization duration recorded from winter and summer fish over the temperature range 4–L22 °C. The major effect of previous environmental temperature was on the duration of the action potential (P<0.02), indicating that the observed changes in pacemaker discharge rate were not influenced by the processes that determine the duration of the pacemaker diastolic depolarisation but were modulated by the channel events that give rise to the action potential.

Original languageEnglish
Pages (from-to)137-140
Number of pages4
JournalJournal of Experimental Biology
Volume198
Issue number1
DOIs
Publication statusPublished - 1995

Keywords

  • temperature
  • cardiac pacemaker
  • action potential
  • adaptation
  • plaice
  • Pleuronectes platessa

ASJC Scopus subject areas

  • Ecology, Evolution, Behavior and Systematics
  • Physiology
  • Aquatic Science
  • Animal Science and Zoology
  • Molecular Biology
  • Insect Science

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