Stereology of cardiac hypertrophy induced by NO blockade in rats treated with enalapril and verapamil.
OBJECTIVE
To quantify the structural myocardial response when chronic NO blockade hypertension is treated with antihypertensive drugs.


METHODS
Four groups of 10 male Wistar rats each were separated as follows: control, L-arginine-methyl-ester (NAME), L-NAME + angiotenisin-converting inhibitor (enalapril), L-NAME + calcium channel blocker (verapamil). All animals' blood pressure (BP) was measured weekly. After 40 days of experimentation the heart mass/body mass ratio (HBR) was determined, and the volume densities of the cardiac components were shown by stereology (Vv[c] for cardiomyocytes, Vv[i] for cardiac interstitium and the mean cross-sectional area of cardiomyocytes, a[c]).


RESULTS
Significant differences by comparison with the control group were: BP increased 71% and HBR increased 24% in the L-NAME group. Vv[c] was 15% smaller in L-NAME animals, while an increase of 11% occurred in the enalapril group and 7% in the verapamil group. Vv[i] increased 20% in the L-NAME group; however, it decreased 13% in the enalapril group and 10% in the verapamil group. a[c] Was 30% greater in the L-NAME group, 13.5% in the enalapril group and 8.5%, in the verapamil group. a[c] Was 12.5% smaller in the enalapril group and 16% smaller in the verapamil group when L-NAME rats were compared.


CONCLUSIONS
Stereology revealed an equivalent effect of enalapril and verapamil in reducing BP, cardiomyocyte hypertrophy and interstitial fibrosis in rats with NO synthesis blockade after six weeks of treatment.
Pereira
L M
LM
Biomedical Center, Institute of Biology, State University of Rio de Janeiro, Brazil. mandarim@uerj.br
Mandarim-de-Lacerda
C A
CA
D000806:Angiotensin-Converting Enzyme Inhibitors / Q000627:therapeutic use; D000818:Animals; D000959:Antihypertensive Agents / Q000627:therapeutic use*; D017209:Apoptosis; D001794:Blood Pressure / Q000187:drug effects; D002121:Calcium Channel Blockers / Q000627:therapeutic use; D006332:Cardiomegaly / Q000139:chemically induced / Q000188:drug therapy* / Q000473:pathology; D004656:Enalapril / Q000627:therapeutic use*; D008297:Male; D019331:NG-Nitroarginine Methyl Ester; D009336:Necrosis; D051381:Rats; D017208:Rats, Wistar; D014700:Verapamil / Q000627:therapeutic use*
D000806:Angiotensin-Converting Enzyme Inhibitors; D000959:Antihypertensive Agents; D002121:Calcium Channel Blockers; D004656:Enalapril; D014700:Verapamil; D019331:NG-Nitroarginine Methyl Ester