Myocardial recruitment during ANF mRNA increase with volume overload in the rat

Abstract

A synthetic oligonucleotide probe complementary to messenger ribonucleic acid (mRNA) encoding for the C-terminal portion of atrial natriuretic factor (ANF) has been used to study the expression of the ANF gene in rat myocardium. Four experimental models were studied: binephrectomy (for 48 h); ligature of both ureters (for 48 h); deoxycorticosterone acetate-salt (for 3 wk); and aortocaval fistula (for 2 wk). Analysis of atrial RNA by gel-blot hybridization detected a single band, corresponding in length to that of mRNA coding for ANF. Such an mRNA was also detected in ventricular RNA but was 1/50th as abundant. In the four experimental groups ANF mRNA was increased significantly as compared with controls. In all rats there was no significant difference in the ANF mRNA content between the left and the right atrium. Each experimental condition was accompanied by a highly significant increase in ANF gene expression in the left ventricle, where all of the ventricular tissue could be recruited and with a negative gradient from the base to the apex of the left ventricle. These data were confirmed by in situ hybridization. Thus all of the atrial and ventricular myocardium can express the ANF gene. Recruitment increases in response to passive stretch of the cardiac chambers.

Release of atrial natriuretic peptide from rat myocardium in vitro: effect of minoxidil‐induced hypertrophy

“…One hypothesis is that ventricular ANP expression may represent a regression of the ventricular myocyte to an earlier developmental form with reexpression of the foetal phenotype, as described for foetal forms of actin and myosin (Wei et al, 1987;Zeller et al, 1987 (Lattion et al, 1986;Gardner et al, 1986b;Ding et al, 1987;Day et al, 1987;Arai et al, 1988;Stockmann et al, 1988;Ruskoaho & Leppaluoto, 1988;Michel et al, 1988). The observations that the endocardial half of the ventricle contained more ANP than the epicardial half (Edwards et al, 1988;Ruskoaho et al, 1989a) also supports the concept of stretch-induced reinduction, because wall tension in the endocardial half is greater than in the epicardial half (Hoffman, 1987).…”

Renal effects of concurrent E‐24.11 and ACE inhibition in the aorto‐venocaval fistula rat

“…Candoxatrilat alone (3 and 10 mg kg-') had no effect on blood pressure when compared to vehicle-treated rats ( (Lattion et al, 1986;Brown et al, 1993). A small proportion of rats fail to compensate for the shunt and die in the first week post-surgery with sodium retention, manifest as pulmonary oedema and _ ascites (Winaver et al, 1988 .…”

Targeting gene expression to specific cardiovascular cell types in transgenic mice.

“…ANF is a vasoactive natriuretic peptide first identified in the granules of atrial cells, from which it is released into the circulation in response to atrial distension (for reviews, see References 50 and 51). ANF is produced by ventricular myocytes in vivo in response to pressure overload, 91 volume overload, 92 or heart failure. 93 Although not entirely cardiac specific, the 5' flanking sequences of both the mouse and rat ANF genes have been shown to confer atrial-specific expression in transgenic mice.…”