Me. Christe et al., CILAZAPRIL TREATMENT DEPRESSES VENTRICULAR-FUNCTION IN SPONTANEOUSLY HYPERTENSIVE RATS, American journal of physiology. Heart and circulatory physiology, 36(5), 1994, pp. 2050-2057
The purpose of this study was to characterize the effect of chronic tr
eatment with an angiotensin-converting enzyme (ACE) inhibitor on left
ventricular function in spontaneously hypertensive rats (SHR). Cilazap
ril (5 mg/kg) was administered in the drinking water continuously for
11 wk, beginning at 4 wk of age. Systolic arterial pressure (SAP) was
monitored weekly. At the end of the ll-wk period, left ventricular fun
ction was quantified using the perfused working heart preparation. Cil
azapril exerted a rapid, complete, and persistent antihypertensive eff
ect in the SHR in vivo but had no effect on SAP in the normotensive Sp
rague-Dawley (S-D) group. Nevertheless, the drug reduced left ventricu
lar weight to the same extent in both strains. Function of untreated S
HR hearts was not different from that of the untreated S-D hearts. Cil
azapril treatment depressed heart performance (28-35%) in SHR but had
no effect in the S-D group. The decline in pump performance in SHR hea
rts was associated with diminished tension development and velocity of
shortening of papillary muscles. These results demonstrate that an AC
E inhibitor, administered to young SHR, produces a reduction in left v
entricular contractile function, which may be due to a decline in musc
le contractility and which cannot be explained exclusively by the redu
ction in left ventricular mass.