© 2001 by European Society of Cardiology
Copyright © 2000, European Society of Cardiology
Hyperactivity and altered mRNA isoform expression of the Cl–/HCO3– anion-exchanger in the hypertrophied myocardium
aCentro de Investigaciones Cardiovasculares, Facultad de Ciencias Médicas, 60 y 120, (1900) La Plata, Argentina
bDepartment of Physiology, University of Alberta, Edmonton, Canada T6G 2H7
* Corresponding author. Tel.: +54-221-483-4833; fax: +54-221-425-5861 gchiappe{at}atlas.med.unlp.edu.ar
Objective: The aim was to examine the regulation of the cardiac Na+-independent Cl–/HCO3– exchanger (AE) mRNA isoform expression in association to the enhanced AE activity in the hypertrophied myocardium of spontaneously hypertensive rats (SHR). Methods: AE activity was determined by the initial rates of the pHi recovery from imposed intracellular alkalinization (forward mode of exchange) and the pHi rise induced by Cl– removal (reverse mode). Net HCO3– (JHCO3–) efflux and influx were respectively determined. AE mRNA isoforms were analyzed by Northern blot with specific probes to detect AE1, AE2 and AE3 mRNAs. Results: Initial JHCO3– efflux after imposed alkaline load (pHi
7.5) was higher in SHR than in normotensive WKY rats (3.01±0.33, n=7, vs. 0.64±0.29 mM/min, n=5, P<0.05). JHCO3– influx induced by Cl– deprivation was also increased in SHR, 4.24±0.56 mM/min (n=10) versus 2.31±0.26 (n=10, P<0.05) in WKY. In arbitrary units, the 4.1-kb AE1 mRNA decreased in SHR (0.15±0.01, n=7) compared to WKY (0.29±0.06, n=7, P<0.05), whereas the 3.6-kb mRNA did not change. AE2 mRNAs were similarly expressed in WKY and SHR. Cardiac specific AE3 (cAE3) mRNA decreased in SHR, 1.10±0.16 arbitrary units (n=8) versus 1.79±0.24, (n=8, P<0.05) in WKY. Full length AE3 (flAE3) mRNA increased from 0.69±0.06 (WKY, n=8) to 1.25±0.19 arbitrary units in SHR (n=8, P<0.05). Conclusions: The increase in flAE3 mRNA expression in cardiac tissue from the SHR is an adaptive change of the hypertrophied myocardium that might be in connection with the increased activity of the AE.
KEYWORDS Gene expression; Hypertension; Hypertrophy; Ion exchangers; Membrane transport
1 http://ftp.genome.washington.edu/cgi-bin/RepeatMasker software.
CiteULike 
Connotea 
Del.icio.us What's this?
This article has been cited by other articles:
|
|
 |
|
  K. Imahashi, F. Mraiche, C. Steenbergen, E. Murphy, and L. Fliegel Overexpression of the Na+/H+ exchanger and ischemia-reperfusion injury in the myocardium Am J Physiol Heart Circ Physiol, May 1, 2007; 292(5): H2237 - H2247. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 J. Dunnick, P. Blackshear, G. Kissling, M. Cunningham, J. Parker, and A. Nyska Critical Pathways in Heart Function: Bis(2-chloroethoxy)methane-Induced Heart Gene Transcript Change in F344 Rats Toxicol Pathol, June 1, 2006; 34(4): 348 - 356. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 B. V Alvarez, D. M Kieller, A. L Quon, D. Markovich, and J. R Casey Slc26a6: a cardiac chloride-hydroxyl exchanger and predominant chloride-bicarbonate exchanger of the mouse heart J. Physiol., December 15, 2004; 561(3): 721 - 734. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 P. Fransen, R. R Lamberts, J. Hendrickx, and G. W De Keulenaer Endocardial endothelium modulates subendocardial pHi of rabbit papillary muscles: role of transendothelial HCO3- transport Cardiovasc Res, September 1, 2004; 63(4): 700 - 708. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
J. P. Versluis, J. W. Heslinga, P. Sipkema, and N. Westerhof Contractile reserve but not tension is reduced in monocrotaline-induced right ventricular hypertrophy Am J Physiol Heart Circ Physiol, March 1, 2004; 286(3): H979 - H984. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 H. E. Cingolani, G. E. Chiappe, I. L. Ennis, P. G. Morgan, B. V. Alvarez, J. R. Casey, R. A. Dulce, N. G. Perez, and M. C. Camilion de Hurtado Influence of Na+-Independent Cl--HCO3- Exchange on the Slow Force Response to Myocardial Stretch Circ. Res., November 28, 2003; 93(11): 1082 - 1088. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
S. M Pogwizd, K. R Sipido, F. Verdonck, and D. M Bers Intracellular Na in animal models of hypertrophy and heart failure: contractile function and arrhythmogenesis Cardiovasc Res, March 15, 2003; 57(4): 887 - 896. [Full Text] [PDF]
|
|
|
|
|
|
H. E. Cingolani and M. C. Camilion de Hurtado Na+-H+ Exchanger Inhibition: A New Antihypertrophic Tool Circ. Res., April 19, 2002; 90(7): 751 - 753. [Full Text] [PDF]
|
|
|
|
|
|
B. V. Alvarez, J. Fujinaga, and J. R. Casey Molecular Basis for Angiotensin II-Induced Increase of Chloride/Bicarbonate Exchange in the Myocardium Circ. Res., December 7, 2001; 89(12): 1246 - 1253. [Abstract] [Full Text] [PDF]
|
|