F. Kristek et M. Gerova, LONG-TERM NO SYNTHASE INHIBITION AFFECTS HEART-WEIGHT AND GEOMETRY OFCORONARY AND CAROTID ARTERIES, Physiologia bohemoslovaca, 45(5), 1996, pp. 361-367
The heart weight and the structure of coronary and carotid arteries we
re studied in NO-deficient hypertension. Wistar rats were administered
L-NAME (50 mg/kg/day) in drinking water for a period of 8 weeks. The
blood pressure and heart rate were recorded weekly. In one group of co
ntrol and experimental animals the heart weight was assessed and the h
eart/body weight ratio (relative heart weight) was calculated. In the
other group of control and experimental animals, the cardiovascular sy
stem was perfused by a fixative under constant perfusion pressure. The
inner circumference and the wall thickness (tunica intima and tunica
media) of the coronary (septal branch) and carotid artery were measure
d using light microscopy and the wall/diameter ratio was calculated. I
nhibition of NO synthase induced a significant increase in blood press
ure (187.2+/-4.2 mm Hg compared to 131.4+/-1.9 mm Hg in the controls,
p<0.01). The heart rate decreased (334.4+/-7.0 beats/min compared to 3
52.6+/-4.1 beats/min in the controls, p<0.05). The heart weight increa
sed in NO-deficient rats (132+/-0.08 g versus 1.10+/-0.03 g, p<0.05);
the heart/body weight index increased remarkably (3.09+/-0.15 compared
to 2.10+/-0.04 in the controls, p<0.01). Morphometry of the septal br
anch of the left coronary artery indicated a decrease of the inner cir
cumference (664+/-24 mu m versus 832+/-30 mu m, p<0.01), the increased
wall thickness (21.15+/-0.84 mu m compared to 12.47+/-0.62 mu m in th
e controls, p<0.01) and the remarkably changed wall/diameter ratio (1:
10 versus 1:21 in the controls). Similar alterations were found in the
carotid arteries: the inner circumference was decreased (2456+/-39 mu
m versus 2732+/-66 mu m, p<0.01), the wall thickness increased (45.14
+/-0.41 mu m compared to 26.08+/-1.23 mu m, p<0.01) and the wall/diame
ter ratio was changed to 1:17 in comparison with 1:33 in the controls,
In conclusion, cardiac hypertrophy and structural alterations of the
coronary artery and carotid artery accompany NO-deficient hypertension
.