Article: The effects of temperature upon contraction and ionic exchange in rabbit ventricular myocardium. Relation to control of active state

The mechanical responses (active and resting tension, dP/dt, TPT) and ionic exchange characteristics (Ca(++), K(+), Na(+)) which follow upon a variation in temperature, rate, and [K(+)](0) were studied in the rabbit papillary muscle and arterially perfused rabbit interventricular setpum. Abrupt changes in temperature provided a means of separating the contributions of rate of development (intensity) of active state and duration of active state to total active tension development (approximated by isometric tension). Threefold changes in duration of active state with proportional changes in active tension can be induced without evidence for alteration of Ca(++), K(+), or Na(+) exchange. Abrupt cooling produced a moderate ( approximately 15%) increase of dP/dt which suggests an augmentation of active state intensity. Evidence is presented to suggest that this increase of dP/dt is based upon an increase in membrane Ca(++) concentration which occurs secondary to inhibition of active Na(+) transport. The alterations in ionic exchange and active state produced by variation of temperature are discussed in terms of a five-component control system.

Citing Articles

Sodium efflux in rabbit myocardium: relationship to sodium-calcium exchange.

Bridge J, Cabeen Jr W, Langer G, Reeder S J Physiol. 1981; 316:555-74.

PMID: 7320882 PMC: 1248161. DOI: 10.1113/jphysiol.1981.sp013806.

Effect of diltiazem on functional recovery and myocardial metabolism during hypothermic global ischemia and normothermic reperfusion.

Kohda Y, Tominaga R, Ueno Y, Tokunaga K Jpn J Surg. 1983; 13(3):246-53.

PMID: 6632397 DOI: 10.1007/BF02469484.

Specific uncoupling of excitation and contraction in mammalian cardiac tissue by lanthanum.

Sanborn W, Langer G J Gen Physiol. 1970; 56(2):191-217.

PMID: 5433467 PMC: 2225861. DOI: 10.1085/jgp.56.2.191.

Effect of temperature and calcium on force-frequency relationships in mammalian ventricular myocardium.

PENEFSKY Z, BUCKLEY N, Litwak R Pflugers Arch. 1972; 332(4):271-82.

PMID: 5064071 DOI: 10.1007/BF00588575.

[Involvement of basal oxygen consumption, activation of myocardium as well as of hemodynamic parameters in total oxygen consumption of the heart].

Krebs R Klin Wochenschr. 1970; 48(13):767-76.

PMID: 4939158 DOI: 10.1007/BF01494491.

References

1.

BRADY A . Time and displacement dependence of cardiac contractility: problems in defining the active state and force-velocity relations. Fed Proc. 1965; 24(6):1410-20. View

2.

OPIT L, Charnock J . A molecular model for a sodium pump. Nature. 1965; 208(5009):471-4. DOI: 10.1038/208471a0. View

3.

Kaufmann R, FLECKENSTEIN A . [The significance of the duration of the action potential and Ca ions in the occurrence of the positive inotropic cold action in the warm-blooded myocardium]. Pflugers Arch Gesamte Physiol Menschen Tiere. 1965; 285(1):1-18. View

4.

Sumbera J, BRAVENY P, KRUTA V . Effects of temperature on the duration and velocity of myocardial contraction in normal and low calcium media. Arch Int Physiol Biochim. 1967; 75(2):261-76. DOI: 10.3109/13813456709089575. View

5.

Shelburne J, Serena S, Langer G . Rate-tension staircase in rabbit ventricular muscle: relation to ionic exchange. Am J Physiol. 1967; 213(5):1115-24. DOI: 10.1152/ajplegacy.1967.213.5.1115. View

The Effects of Temperature Upon Contraction and Ionic Exchange in Rabbit Ventricular Myocardium. Relation to Control of Active State