HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text Full Text (PDF) All Versions of this Article: 290/2/H778    most recent 00808.2005v1 Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in Web of Science Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Web of Science (1) Citing Articles via Google Scholar Google Scholar Articles by Yatani, A. Articles by Deitch, E. A. Search for Related Content PubMed PubMed Citation Articles by Yatani, A. Articles by Deitch, E. A.

Dual effects of mesenteric lymph isolated from rats with burn injury on contractile function in rat ventricular myocytes

¹Cardiovascular Research Institute and Department of Cell Biology and Molecular Medicine and ²Department of Surgery, University of Medicine and Dentistry of New Jersey-New Jersey Medical School, Newark, New Jersey

Submitted 29 July 2005 ; accepted in final form 5 October 2005

Gut-derived factors in intestinal lymph have been shown to trigger myocardial contractile dysfunction. However, the underlying cellular mechanisms remain unclear. We examined the effects of physiologically relevant concentrations of mesenteric lymph collected from rats with 40% burn injury (burn lymph) on excitation-contraction coupling in rat ventricular myocytes. Burn lymph (0.1–5%), but not control mesenteric lymph from sham-burn animals, induced dual positive and negative inotropic effects depending on the concentrations used. At lower concentrations (<0.5%), burn lymph increased the amplitude of myocyte contraction (1.6 ± 0.3-fold; n = 12). At higher concentrations (>0.5%), burn lymph initially enhanced myocyte contraction, which was followed by a block of contraction. These effects were partially reversible on washout. The initial positive inotropic effect was associated with a prolongation of action potential duration (measured at 90% repolarization, 2.5 ± 0.6-fold; n = 10), leading to significant increases in the net Ca²⁺ influx (1.7 ± 0.1-fold; n = 8). There were no significant changes in the resting membrane potential. The negative inotropic effect was accompanied by a decrease in the action potential plateau (overshoot decrease by 69 ± 10%; n = 4) and membrane depolarization. Voltage-clamp experiments revealed that the positive inotropic effects of burn lymph were due to an inhibition of the transient outward K⁺ currents that prolong action potential duration, and the inhibitory effects were due to a concentration-dependent inhibition of Ca²⁺ currents that lead to a reduction of action potential plateau. These burn lymph-induced changes in cardiac myocyte Ca²⁺ handling can contribute to burn-induced contractile dysfunction and ultimately to heart failure.

cardiac myocyte; action potential; calcium currents; potassium currents

This article has been cited by other articles:

				J. T. Sambol, M. A. Lee, F. J. Caputo, K. Kawai, C. Badami, T. Kawai, E. A. Deitch, and A. Yatani Mesenteric lymph duct ligation prevents trauma/hemorrhage shock-induced cardiac contractile dysfunction J Appl Physiol, January 1, 2009; 106(1): 57 - 65. [Abstract] [Full Text] [PDF]

				K. Kawai, T. Kawai, J. T. Sambol, D.-Z. Xu, Z. Yuan, F. J. Caputo, C. D. Badami, E. A. Deitch, and A. Yatani Cellular mechanisms of burn-related changes in contractility and its prevention by mesenteric lymph ligation Am J Physiol Heart Circ Physiol, May 1, 2007; 292(5): H2475 - H2484. [Abstract] [Full Text] [PDF]